Delia,
This is lenny again , to answer some of your questions, I found that rinsing with salt water helped as did using crest non alcohol mouth wash. Is charlie having issues with dry mouth? if not he may have in the near future I found that the hard candy "lemonheads" work very well for this.
I had 33 radiation (IMRT) treatments that ended 12/16/05, yes my neck was burnt black but oddly enough not sore at all it was like dead skin after a very good tan and it healed very quickly and nicely, It was pretty much healed by the time I had neck surgery 3 1/2 weeks later. I did have three rounds of chemo (cisplatin) and had no side effects at all from chemo. I hope that this info helps a bit more.
always lenny