Hi Laurie - sorry you have to be going through all this but it sounds as if you have a great attitude, and of course your knowledge as an MD will help (or maybe you know too much

!)
All the advice these folks have been giving you is great - the nutrition, the swallowing all the time, the various salves and such. You didn't mention whether or not it was recommended that you get a PEG. I did not, but found that a few weeks into rads I wished I'd had because of mouth sores. So it's certainly something to consider.
The mask is also pretty daunting, but I found that listening to music or an audio book during treatment was a lifesaver.
Please continue to ask questions here. You're part of our family and we're here to help. I know it's fatuous to say "don't worry", but I hope that the continued info you're getting here will help you achieve equilibrium while you await treatment.
I'm sure you'll come through it with flying colors!