Radiation. Thank goodness for it and damn it too. I think that Steve is right when he said "Radiation treatments will continue to change things in your mouth and throat". That has certainly been the case with me. I got some great advice here about rinsing my mouth with a mixture of warm water, baking soda and salt. I found it to be very soothing. Just keep your mouth as clean as you can. Humidifier is a great idea for overnight too.
I am three years out from radiation and, although you may not find this particularly encouraging, I still have sores in varying locations most of the time. When they "flare", I go back to softer foods, rinse my mouth often and talk less.
I had a devil of a time with radiation and talking was super painful etc...that went away with me. I have experienced some periodic, location specific swelling of my tongue as well, but that tends to pass fairly quickly.
You may find that your neck and into your shoulder and upper back gets sore and stiff, and I have also experienced vertigo. Am seeking physio for stiff and sore neck and the vertigo only happens once in awhile now.
Hang in there! It takes time and every journey is a little different, but life gets good again. All the Best.