How can a nasal tip be lengthened in order to derotate please? Will I require grafts?

You need a real expert in revision cases; I have read your other posts here and answered one; I tried to imagine your situation, but I have to request from you images to assess on grounded facts your situation and possible solutions.Yes, it is feasible to derotate a so-called piggy nose; as per your explanation you might have septal over resection; the solution is a septal lengthening one-on-one plus 2 caudal extension strut grafts, a very delicate and high-end technique to which us rhinoplasty surgeons are familiar with. Eventually and likely you may need tip or shield (tip+columella) grafting.This new scaffold may work to attach to it the cruras of the tip and restore its projection to the desired level; a routine in major caudal revisions.The donor site, if the septum is no longer available, has to be the ear conchas or, may additional amount be necessary, the rib cartilage.If you got a wronly indicated tongue-in-groove... technique I am familiar with... and it has been associated with a caudal septum resection... caudal septum which is the fixation point of tip's cruras during a tongue in groove... I can imagine what a mess of nose you are suffering now; tongue in groove should never be secured to a too short or trimmed septum!Such peculiar name (tongue in groove) is given to a not very modern but nowadays extremely trendy (to much in my opinion) surgical maneuver consisting in a securization by sutures of the medial cruras of the alar cartilages onto the caudal septum, caudal septum which is used a secure fixation point and columellar strut at the same time. Depending on the design of the anchoring angle, projection and depth the grade of the procedure and its effect will be different, due to this the tongue-in-groove technique may work, individually or in a flexible combination, to:
-deproject or overproject a tip: using the caudal septum as columellar tutor / strut / support to lengthen or shorten the medial cruras
-hide an overprominent or overexposed columella: the wrongly called "hanging columella" can be sunk and retroceded inward the nostrils by the push-in effect made
-correct and secure the senile ptosis of the tip (droopy tip): aging patients with thich skin as a heavy burden on a tip with weak ligaments may develop a droopy tip; to lift the tip it is enough reducing its dowards projection support, spontaneously the tip will be lifted by the tissues contraction, but this might fail in a senile patient, so securing the cruras to the septum guarantees the elevation of the tip
-correct the hooked nose in ethnic cases: when the nasolabial angle is very closed and the tip has a deep angle downwards (as in senile noses but due to congenital ethnic causes), and if additionally the skin is very thick and has a lot of memory... an spontaneous elevation of the tip may fail after trimmint is caudal support, so securing the cruras may be a good decision in some cases (arab noses, etc).
-rotate a tip: in some difficult cases, or custom requests to obtain certain effects like an upwards tip, you can achieve that trimming the caudal septum but this leads to collapsed tips, short noses, sunken columellas, etc, it is way better using the tongue-in-groove securization in custom design
The surgeon can freely design the tongue-in-groove gesture so as to achive only one of the former wished effects, or more than one, and each of them graduated with precisoin, since the tongue-in-groove is a technique of WYSIWYG, stays exactly in place and is extremely unlikely to fail or experience the minimal modification overtime.
The pros of the gesture:
-when properly indicated and clearly required is a "must", has no equal substitute
-its versaility, you can design it to comply with varied (see above) anatomical effects
-WYSIWYG, stays wherever and however you have executed it intraop
-stable overtime, very rarely experiences de-gradation or de-correction overtime
-needs no major dissection or aggressiveness
-medium difficulty technique, accessible for the average nose surgeon (this is one of its cons, read on), however it is very difficult to calculate the right grade of corretion and its design
-is an extremely powerful tool, each tiny degree of correction is multiplied in real external anatomical shape effects, applies the rule do 1 and you get 5 (this also makes it dangerous)
-in case of mistake is fully reversible and / or can be re-graduated and re-designed
The cons:
-being feasible (and such was originally described), I strongly advise all my respected colleagues aginst performing it by means of a closed approch, the open approach is a must; in a closed approach is practically impossible to apply a perfect customization of the effect and way lesser possible set the right gradient of each goal planned, being the chances of a random, unwanted and unsighty effect too high, or also a possible over or undercorrection; open approach is a must (something similar applies to Sheen's or other tip grafting, feasible and originally described by closed or marginal approach by the masters pioneering the technique, however accuraty is impossible without open approach and fixation of the graft with total surgical control)
-being such an extremely powerful maneuver... poses a real danger in non experienced or non judicious hands; if done in non indicated cases, if planned wrongly its design or if the gradient of the effect is not accurate... the result is a mess, catastrophic or grotesque, like a gun in a monkey's hands
-not being a procedure of very high difficulty is accesible to most average level surgeons performing rhinoplasty, and this poses a risk of over indication, over execution or indication without criterion or need
-has become, for all the former, a kind of trend, yes, a trendy topic in courses, seminars, congresses and scientific papers, it makes feel like The King saying "hey guys, I perform the tongue-in-groove in all my cases, see my series, aren't I cool?"; too many reckless teens performing termonuclear maneuvers in noses, hope you get me
-tongue-in-groove should be very judiciously indicated, performed and graduated, I am fan of the technique and I regularly use it in chosen cases (revision of disasters, ethnic, aging, custom rhinoplasties, etc); otherwise... you get very unsighty effects like: sunken or hidden columella, over (Pinoccio) or underprojected (polly beak) noses, over rotated tips, piggy noses, exposed nostrils, etc.
I understand you got tongue-in-groove by means of closed approach, I guess after reading my text you understand now why you got an over rotated tip and a piggy nose, and this answers your main question: yes, you need a revision, and it has to be under open approach... actually the first procedure, considering you were scheduled for a tongue-in-groove, had had to be by open access (reasons explained above) and a better experienced surgeon. Needless to say, my prognosis is your tip will not come any lower in the future, since it has been firmly secured to the caudal septum; the sutures may dissolve overtime, but not the fibrosis between the cartilages, this is the pearl but also the pitfall of the tongue-in-groove maneuver.
Furthermore, let me tell you the following: no matter how much you read or you are told by surgeons, it is a reckless, irresponsible and  catastrophic decision trying to do a revision rhinoplasty in your case by closed approach; and in general any major grade or high-end nasal overhauls have to be, NECESSARILY, done with open approach and direct visualization, this is an undisputable fact to be agreed by any surgeon performing SUCCESSFULLY revision rhinoplasties. Moreover, you must be really obstinated, stubborn and unwise if you try to lower a tip which has be massively fixed to the caudal septum by a mass of fibrosis and scars.
The good news is the procedure can be re-graduated, re-designed or even fully reverted, however this is an extremely delicate maneuver (great care has to be taken to navigate among the fibrosis between the septum and the medial cruras, avoiding specially any damage to the cruras) which should be done ONLY by a very experienced revision rhinoplasty surgeon who, as well, enjoys vast experience in the tongue-in-groove procedure (and if not asking much who reads attentively your case details). It is unclear if you might need additional grafting to lower that tip, to be assessed if you allow viewing images. Difficulty of your revision is very high, 8-9 out of a 10 scale or difficulty, surgical time 3-4 hours plus the other enhancements your nose might (likely) need. I strongly recommend you find a real expert in revision, save the money and travel wherever required, but don't waste your last chance of repair, which exists.
Please do post or send privately a full set of good quality, well lit and focused standard photos: frontal, both lateral views and both oblique views, also from underneath the nostrils.
Feel free to request any additional information from me.

The key to lengthening the nose through de-rotation of the tip is placement of a strong septal extension graft.  This stable graft serves as an anchor point to leverage the tip cartilages down against the soft tissue constraints imposed by the skin covering and scar tissue.  See my educational video below.