I agree with the other girls, Oil of Clove or if you don't have that, grab a clove and shove it against the gum where it is sore. The Romans used to use clove against sore teeth while on forced marches (they also used to munch on fennell seeds to stop hunger pains).

This is going to sound really bad - but go to a "poorer" area of the city and find a chemist there - they're probably more used to having people who can't afford immediate hospital treatment coming in for over the counter remedies.

Good luck with it all.