And by "better" I mean "cured". Thank you all so much for your wonderful comments! You were very comforting.
Here's what I learned from this experience, dear readers:
do not self-diagnose using the internet.
Due to all the weird symptoms, and with the help of Google, I had decided I had trigeminal nerve damage and that the rest of my life was ruined. I would be doomed to swallow prescription pain killers for the next fifty years and, if I was lucky, I could save up enough money from bake sales and contract knitting, that I could go to a special clinic in the US and have ground-breaking laser surgery that would of course go horribly wrong, leaving me with bi-lateral paralysis and probably a hunchback.
But in the end, the dentist turned out to be right (who knew that 30 years of doing a job would make you good at it, eh?) and it was an abscessed tooth. Even though that tooth never hurt me even once.
So rejoice with me, for I can do all of this without pain:
* eat fruit out of the fridge
* go for a walk in the freezing night (six months from now, I mean)
* go swimming in glacier-fed rivers (I do that in August)
* drink water at room temperature or cooler
* talk while I am smiling!
And I'm doing that last thing right.....now!