I'm having the same reaction and my team recommended I use miracle mouthwash. This is a combination of three things at 60 mL then you take 5 mg up to five times a day and swish it and swallow. There is an article here about it. This is the name of the post. "Magic mouthwash: Effective for chemotherapy mouth sores?" Good luck.

Also, study about the vagal tone. I'm really interested in this and have been spending the last six months taking small family trips and reconnecting with friends. It seems to really be helping me feel better.