Will the antibiotics treating the infection, treat an abscessed tooth?

My fiancee is on antibiotics for an infection in teeth 30 and 31. (Back teeth, lower right jaw) He is on antibiotics. Last night (day 1 of the antibiotics) he noticed a bump on the gum (pretty high up) of one of his front teeth (not causing any pain). If this is an abscess, will the antibiotics treat it? Or should we take him back in? We plan on a consultation in a week or so (after he's done with the meds) for the root cs.