I have had a similar thing (not quite as bad as you describe) recently and i mentioned it to my GP while i was there about other stuff and she said it looks a bit infected...dont know how.

I was given a script incase i needed it but have'nt bothered with it.
My tongue still looks a bit ordinary but its not hurting anymore.

Not sure if its the same or not !

Goodluck - i agree - it does hurt.
xo