Dude, just go to the doc....PLEASE....the abcess should be cultured to see whats in there....THEN you decide what anti b to use.....it depends on the organism and its suceptibility when deciding treatment.....
I see way too many people on vanco and newer carbepenims in the hospital...too many drug resistant infections...if you are going to treat it, get a profesional to do it right....
Not to mention, as stated above, although an oral agent will work, the abcess should be lanced and packed.
Erythro is a little dated, more sides than the newer doxy......i better stop before i go on for hours about anti-bs