The main stay of treating trismus are the exercises, although limited, and use of the Dynasplint, Therabite. There is Pentoxifyilline, and micro-current electrotherapy that may help some, and surgery, coronoidectomy, but the problem with that is the radiated area is more widespread, involving adjoining muscles, so the problem could arise again with fibrosis of these areas.

Do you measure the mouth opening? Mine is about 1/2 inch, from top to bottom teeth, which may be about 12mm, which is severely restricted on several type measures grades, not that it changes much for the problem.

Tell the doctor, who may have to rule out any recurrence just to be on the safe side. Good luck.