Trismus is very scary, can worsen suddenly, and is very difficult for a caregiver to watch. You asked about referral to a specialist -- Our situation is different in that my husband's trismus was related to a dental extraction post treatment. We ended up with oral surgeon at Mt. Sinai/Beth Israel Hospital in NYC Institute for Head, Neck & Thyroid Cancer Department. Someone else on this forum consulted with an Oral Medical Specialist at Tuft's Dental School.

I'm sorry to say that it is difficult to get to the correct dental person... the dentist your husband saw is a dental oncologist? There are very few so that's unfortunate about his manner of approach at such a delicate time in your husband's recovery.

I started to type much more but it may not apply to your current situation. Feel free to ask here or PM (private message to me under My Stuff tab at top) for more details.

I hope thoracic consultation goes well and will be thinking about you.