I was fortunate that my CCC recommended a prothodontist who specialized in oconological dentistry. He sees a lot of oral cancer patients but is not affiliated with the CCC.
You may be reassured that after my 33 first radiation treatments and 8 chemos, I developed a similar issue with my left wisdom tooth but even worse, the wisdom tooth had developed a crack. The opinion was that an extraction risked jaw osteonecrosis so I had a root canal done and then a crown fitted. It was very very tender for almost a year before settling down (of course since I haven't eaten any food nor chewed since February that may be a factor). This was on top of getting another root canal in the molar next to the wisdom tooth that had already been crowned. It can't hurt to ask for a recommendation from the CCC and I was sent to a root canal specialist who operates through a microscope instead of the jeweler loupes type magnifier like my other root canals were done. He could do the entire root canal in one session. You are right to be careful and worried and your husband is lucky to have you as a caregiver
charm