Hey Cheyenne -
I may be a bit late with this - my oncologist had sent me to the dentist in the hospital who made me a pair of mouth guards on the spot. Basically just filled a tray with some putty-like substance, had me bite down, and then let it harden.
I wore those to every radiation treatment session. I think they were originally supposed to be used for flouride treatments.
At one point after examining me, he also had me wet a piece of gauze and place it inside my mouth. It's been seven years and those days are a bit foggy.
Ask your radiation oncologist about the mouthguards. I tmay help.
Wishing you light side effects and a rapid recovery!
- Jeff