Your surgical site, because of pre-existing infection, has been purposefully left open to allow continued drainage for a few days. It has a small ribbon of antibiotic impregnated gauze partially filling the space where the infection was drained. The tail of the gauze ribbon is left protruding through a small band-aid covering the site.You should change this outer layer of tape periodically as it gets dirty or after a shower when it gets wet. Leave the band-aid and ribbon arrangement in place for 48 hours. At that time you should pull the band-aid off, removing at the same time the antibiotic ribbon from the wound (discard them). It would be advisable to gently clean it well in the shower daily thereafter with soap and water.
The idea is to allow it to heal from the bottom of the wound with the outer layer of skin healing last. The wound typically heals very nicely, with a small scar over a period of several days to weeks or so (depending on the size of the original abscess). After the inflammation has subsided, there may be some residual cyst evident. If necessary, this can be removed electively 1-2 months later with a small in-office procedure.