Nelie, I may give you further encouragement because I am a school teacher too! When I lost my voice after treatment, I also had the greatest fear that I wouldn't be able to teach again but I was wrong! I resumed teaching 7 months post treatment and despite some changes to my voice, strangers would never notice that I had cancer treatment. I have taught for about 3 years after my illness already and I manage to speak clearly with a few sips of water in every lesson. I depend a lot on sugar free candies and chewing gums which help to give me some moisture in the mouth. Without them, my voice would go very raspy. Of course I have to use a mic in the classroom but all my colleagues need one too because the class size is very big compared to yours. It can be as large as 40 students in one class.As about singing, if I want to sing in a group, I can but the best time singing is while I am in a bath! I didn't have healthy teeth before treatment but I managed to keep them all and I still have all my teeth now and my dental health is even better than before.
I didn't have IMRT and so mouth dryness is the most frustrating side effect I have so far. Since my tonsil cancer was at a stage 4B (T2N3M0), I had radiation to both sides of my neck. I just had chemo and radiation but no surgery. I understand all your fear and worry because I had been there before. Be positive and I am sure you will enjoy your "new normal" when the nightmare is over. Ask any questions on this forum and I am sure you will get them answered by knowledgeable and supportive members.

Karen.