Please describe a good antibiotic to treat an ear piercing infection?

Topical or oral?: Usually you can get away with a topical antibiotic to treat these infections. Something like bactroban locally usually does the trick. However, if the infection is severe enough to warrant oral antibiotics, then keflex, Bactrim or Augmentin (amoxicillin and clavulanate) might be reasonable choices depending on how much MRSA is prevalent in your community. Your doc should know this and pick accordingly.