In answer to your question yes it does happen. Sometimes particularly after rads there will be a sore that takes forever to heal. Your mouth is Very sensitive at this point and healing is compromised. I had one on my tongue that was exceptionally painful it was rubbing against a molar. I had the molar filed down and it healed - then I had another from where the radiation came in contact with my tongue (entry point?) and it took forever to heal. They were going to biopsy it - I became super diligent about cleaning and apply the cortaid my ENT had prescribed and it went away (but took a month and a lot of coaxing.

hugs.

Sometimes a sore is just a sore.