Extreme tightness after sliding genioplasty

It’s been 1 year post-op genioplasty and I am continuing to have extreme tightness on my chin, teeth and lower gums. It sometimes even hurts. I have googled and researched for answers on what this could be, but haven’t found any. Now I am not sure what’s causing this. Some say it’s the mentalis muscle and others say it’s a scar contracture. The tightness is deep inside the incision line. If anyone went through the same thing and found a solution for it, please let me know