In brief: Depends on severity. A tiny pimple or pustule on the skin, caused by regular staph, should heal up in 3-5 days after the pus comes out. A deeper abscess may take 1 week of treatment to clear up, and another week for the remaining wound to heal. People who have internal abscesses in their bodies, or have suppressed immune systems, can take several weeks of treatment with IV antibiotics (even longer in bone infections).