It does sound like it could be an infection indeed.

If I was in your position, I would apply Colloidal Silver to it daily and then eventually have it dealt with by a true biological dentist. I would never let a conventional dentist touch this sort of thing because you don't know what they're going to fill it with.

Using colloidal silver, I would just dip the end of a Q-Tip into the silver and then place it on the "pimple" for about 3 to 5 minutes 1 to 3 times per day. There should be some improvement quickly and this should help until something more permanent can be done.