Oral And MaxilloFacial Surgeon
12 yrs exp
Unless a ctscan or an x-ray suggest that there is a fracture, you need not worry about the tmj pain. After your fall, and direct injury to the chin, there is an indirect jerk in the tmjoint. This indirect jerk causes minor blood vessels to disrupt and leak blood into the joint space. So even if 1 ml blood is extra in the joint, the movement becomes stiff and hence the pain.
You might consider using ice packs alternatively with moist heat to improve blood circulation and reduce pain. Medicines will be prescribed by your doctor. Visit with scan or X-ray.
Is the pain while you open the mouth wide or spontaneous? Can you detect any change, even minor, in your occlusion (the way your teeth close upon each other)? How many days have passed since your accident?
Most common chin accidents are accompanied by a minor crack in the condyle (the joint portion of your mandible near the TMJ). But if your dentist has ruled it out, I presume a ct or a cbct has been done for the jaw. If not, please get them done. If yes, there must be a soft tissue/disc injury which often resolves on its own, but if it doesn't, please consult a maxillofacial surgeon in your city.