I'm sorry for your difficulty. I had a newer form of high dose brachytherapy called IORT, twice, during radical neck dissections. I managed pain with oxycodone, and Gabapentin for nerve pain, which I was already taking for neuropathy, and wasn't that bad, thankfully, but the tongue may have more pain receptors.

I can relate to the opioid problem here, which have restrictions in prescribing and filling. Some doctors won't prescribe anymore since their required to check and keep tack on a state database, some people go prescription shopping, and the same with filling at pharmacies, sone who didn't carry them anymore, were robbed. I had difficulty obtaining some with my PCP for a painful tooth abscess, so I went to my CCC palliative care doctor, who prescribed opioids, nerve pain meds, no problem, but then I had to check with or go to a total of 10 pharmacies to have filled, having certain stares, side conversations and outright refusal by the employees, pharmacist

Good luck.