Hi, Len, mouth sores are definitely a side effect that applies to nearly all if not all oral cancer patients. I had to take pain medicine and mouthwash products prescribed by my doctor to relieve the pain. I didn't have antibiotics because the sore was not an infection in my case. The gargle I took could numb my mouth for a short while so that I could eat my meal without much dfficulty. The mouth sores could last for quite some time but I can't remember for how long but I could eat most of the food about 4 months post treatment. I never had a PEG tube. By the way, there is still some minor sore along the sides of my tongue even today but it doesn't affect my speech and eating. Hang in there, the sores will fade away gradually but may take a longer time. Everyone has a different healing schedule.

Karen.