Should I find an ortho max to reverse sliding genioplasty or a plastic surgeon? (Photo)

You might well be victim of a poorly planned and aesthetically wrongly judged geniplasty, as per the image you got a two-dimensional augmentation with the step-off method (which I dislike and may lead to problems, I prefer to fill the gap with natural and own patient's bone grafting); additionally you got plate and screws, which sooner or later will require removal, I strongly advocate wiring which is way more versatile and never had to remove.As per your words you feel you got an over correction, this should not make you think you have to revert the genioplasty, you just need to RE-ADJUST or graduate correctly the augmentation, or reassess which axis have to be touched. Additionally if your chin is too broad why not narrowing it?It is an epidemic problem the osseous genioplasties carried out mechanically into an authomatism of planning, and not individually customized. Keep in mind the immense versatility of genioplasties, which allow the surgeon to increase or decrease the height, the width and/or the projection or the chin, in all the combinations possible you could imagine and more.Seek the opinion of a surgeon who is expert in geniplasties, just this.
I perform regularly all kinds of genioplasties, not only sliding
genioplasties but also one, two and three-dimensional augmentation
and/or reduction genioplasties, plus other custom designs; in other
words, I know well what I am talking about.This is an awesome, lifetime lasting, stable and safe procedure, which
notwithstanding needs very accurate preoperative antropometric
planning, desing, discussion and a brilliant execution, a technique full
of creativity and good aesthetic judgement requirements.
Chin implants have many disadvantages:
-visibility, static or with facial gestures / smiliing
-artificialness, fake look, evidence of implant presence

-limited lack of versatility, they do not provice vertical modifications neither reductions
-common infections
-common dislocations
-possible nerve irritation and pain
-short lifetime
So sooner than later they are normally removed, or exchanged by an osseous genioplasty.
Why
so popular (chin implants) then? Simple answer: they are technically
accessible to all surgeons, little training is required, can be done
under local and sometimes office based procedures, they are cheap.
Osseous
geniplasties are more expensive and need good skills, true, but when
performed they produce lifetime results, safe, stable overtime, very low
rate of complications, versatile three-dimensional modifications
(augmentation or reduction, vertical, horizontal and depth), low rate of
reinterventions, etc.
Feel free to request any additional information from me.

Those of us who have had craniofacial training beyond plastic surgery training have experience with this sort of suboptimal outcome. You may want to consult a craniofacial plastic surgeon since reversing the a sliding osteotomy may have some adverse consequences, understanding of which is essential to having a pleasing outcome. Rather than reversing, an experienced surgeon may suggest revising the osteotomy, meaning keeping the advancement but shortening the chin to minimize the lengthening effect of the advancement on your face.  

You need to have your sliding genioplasty partially or totally reversed by a surgeon who has experience in doing so. Look for someone who can show you examples of such surgery.