Hi Steven,
I don't have any advice for your headache or light headed feeling, but I can give you some suggestions for the dry mouth. I am 9 mos out of similar treatments that you had. The dry mouth is the most irritating side effect for me. I've found several things that really help. One is that I have a small humidifier in my bedroom at night. It helps to keep the air moist which in turn helps keep my mouth from drying out so much. Another thing that really seems to help is using ACT mouthwash with flouride several times a day. It is very mild and doesn't burn. I was using the Biotene mouthwash but it didn't seem to help with the dry mouth as much as the ACT does. That's my personal opinion. Anyway, I hope this helps and I hope your headaches will go away real soon. Hang in there!