My father has what started out to be csyst in the middle of his back, 3 weeks later it was the size of a marble and ozzing yellow creamy puss. I wiped w sterile gause drained onto e 4x4 gauze applied triple antbiotic (bacitracin) Add covered w 2 4x4 gauze. Changed dailey 3rd day today.
Dear friend, Your father having a back cyst with discharge from it. I would like to know the duration of that swelling. If it was there since long time and recently showing a discharge, then it may be infected sebaceous. And history of swelling of few days with discharge, mostly a boil or simple abscess. Simple abscess may heal with Chat Doctor.  But if it is infected sebaceous cyst then it needs surgical excision, because remaining cyst wall may lead to recurrent cyst. Thank You.