Can Grafts Give Nose Tip a 90-degree Angle?

A nose-lip angle of 100 degrees is acceptable, and undergoing another Rhinoplasty to de-rotate your nose may lead to disappointing results. It is theoretically possible to use cartilage grafts to lengthen your nose, but your outcome may be somewhat unpredictable. Your tip will tend to de-rotate over time just from the effect of gravity, so my feeling would be to hold off on further surgery for now.
If your bridge is too low, you could consider Injectable Fillers to increase the height, and improve your appearance.
I've attached a link to my Non-Surgical Rhinoplasty photos for your perusal.
I hope this helps, and best regards.

Lengthening an over-shortened nose is one of the more difficult things in revision rhinoplasty. It can, however, often be done. Unless there is still a lot of good septal cartilage remaining, rib cartilage is the next best thing: it provides a lot of grafting material and is of good strength. Its dimensional stability is good, but only if care is taken to shape balanced grafts.
Patients undergoing this sort of correction can also expect to have a nose that--while looking better--will feel much stiffer at the tip due to the requirements for stabilizing the grafts. Special care also needs to be taken to camouflage the grafts so that they don't produce obvious knuckles over time and patients should be aware that improvement, and not perfection, is the reasonable target, since complete correction is sometimes impossible.
All the best,
--DCP

An over rotated nasal tip can be difficult to de-rotate. However, a number of technqiues can be used to de-rotate it. This can be achieved by wide dissection, tip sutures, as well as grafting to the septum to basically push the tip down.

Your problem can definitely be corrected with a revision rhinoplasty. It is not easy to lengthen and counter rotate the nose, but with the appropriate type of cartilage graft it is definitely possible. Depending on the size of your nose and available tissue left behind, your surgeon may need to use cartilage from your rib which would offer plenty of "new" tissue for the revision operation. An experienced rhinoplasty surgeon should be able offer you the help you desire. Best of luck.