I was a very slow healer post RT. My RO stated I was the slowest healer he ever saw. I agree with the advice given above and be patient Also, avoid food that is acidic, spicy, sharp or hard and hot. I would frequently get painful mouth ulcers often triggered by something I tried to eat. My RO prescribed various mouth rinses and eventually a medication called trental combined with vitamin E to promote healing. I eventually had HBOT (which did help) but that was about 2 years after RT.

Good luck and try to be patient!