Rick, I'm halfway through 35 radiation treatments and 7 chemos. (My 18th rad is tomorrow; 4th chemo was Monday.) It's less scary once it starts. You settle into a routine.
My treatment team emphasized the baking soda/salt rinses, which I've done religiously, and I don't yet have any mouth sores. Which isn't to say I won't, or that the next five weeks won't be awful.
But what I've found so far is that I can deal with what's in front of me today with much less anxiety than worrying about how things might be two or three weeks from now, which I can't know and can't control.