Definitely look into neuromuscular facial retraining! What you are describing sounds like hypertonic muscles - in laymen's terms, your muscles are spasming. Speaking form experience, this can be very painful not to mention disfiguring. I started getting this in my cheek at about a year post. I ignored it (stupid!) until it got so bad that I was using the heating pad on my face every few hours. At the same time, I started to get synkinesis (that would be the dimpling in the chin). Finally, almost 2 years post op, I went to Wisconsin to spend 3 days with Jackie Diels - best thing I've done! The improvement has been amazing, the pain is gone, my lip isn't pulled up into a snarl anymore ... and so on.
Please feel free to PM me if you want Jackie's contact info. If it is not feasible for you to travel to her, she can give you the name of someone near you since she has trained so many of the NMFR people around the US and Canada. Just don't ignore it! The hypertonicity could go away on its own, although for most of us it doesn't. And, the synkenisis won't go away, all you can do is learn to retrain the muscles to minimize it.
Good luck!
Debbi