Hi Vicki,
I wish I could help you but I honestly haven't had any of those symptoms, in fact, one of the surprising things about head and neck cancer is it's lack of pain (pre treatment of course). Some of your symptoms are similar to my post treatment conditions but milder than your description.

I have a very close friend who has acute systemic lupus however and what you describe sounds very similar to what she has been going through. As Brian said in his post, your symptoms are "...are very troubling and potentially dangerous " and I would certainly have a head and neck surgeon do some diagnostics just to rule it out, particularly since you are a cancer survivor. Lupus management and diagnosis is a specialty in it's own right.

Most of us have to deal with dry mouth and tooth decay for us could have very serious consequences due to Osteoradionecrosis so I have had dental trays made and apply flouride several times a week as a preventative measure.

I wish I could be of more help.