Steve,
there are some good suggestions here. When things were bad for me I used viscous liocaine. I diluted this 1:2 and swished it around and also swallowed some (helped swallowing/eating). Unfortunatly the relief is only short term. I also used Aquaphor for lips.

Not to hijack this tread.... about on month after the end of the radiation I ended up getting blisters (top of mouth, soft palate) and on the inside of lip. The blisters (up to 7-10) appered when eating and had trapped fluid. (ca 1-3mm in diameter). They do/did not hurt and vanish within an hour or so... and reappear at different positions next time. Now I get only a few and rarely but always when eating. Presumably small glands are getting busy again?
Has anyone else encountered this?

Markus