Need to drain a painful blister? To avoid infection, follow these steps: Wash your hands and the blister with soap and warm water. Swab the blister with rubbing alcohol, and sterilize a clean, sharp needle with rubbing alcohol. Puncture the blister at several spots along the edge. Let the blister drain, but leave the overlying skin alone. Apply antibiotic ointment and cover with a bandage. After several days, remove the dead skin with sterilized tweezers and scissors. Apply more antibiotic and a bandage.