I have a terribly swollen throat and difficulty in swallowing 2 days after an intial root canal treatment. My dentist has prescr

When he did you root canal, did he drill through a metal filling? You could have mercury poisoning. Metal fillings contain Mercury, and despite what you are told, they can make you very, very sick. Mine nearly killed me, literally. I had a dentist drill through one, too...when he gave me a root canal. A piece of the metal got lodged in my jawbone, and was in my bloodstream. I couldn't swallow and my neck was swollen. If you don't have metal fillings, it could be a cavitation (bacteria) in your jawbone. 

Hope this helps!