Consider if you should drain the blister. Usually, you should leave an unpopped blister alone to prevent aggravating it and making the infection worse. But, if your blister is on a joint and places pressure on it, you may want to drain it.
Draining the pus can relieve the pressure and reduce pain. Keep in mind that you’ll need to monitor the blister and keep it bandaged and clean after you drain it.
Clean the blister area. To prevent the spread of infection, wash your hands and clean the blister. Wipe the area around the blister with rubbing alcohol or an iodine solution to kill off any bacteria on the skin.
You should also disinfect a needle by swabbing it with the rubbing alcohol or iodine solution or holding it in a flame for about a minute.
Pierce the blister. Take the disinfected needle and pierce the skin at the base of the blister. This should be near the bottom of the blister. Make several holes so that the fluid can drain out of the blister. Avoid applying a lot of pressure which could cause the blister to burst open.
You might want to take a cotton ball or piece of gauze to dab or wipe up the fluid or pus that leaks out of the blister.
Wash the infected area out with either hydrogen peroxide, saline or soap and water. Do not use alcohol or iodine as they will irritate the wound.
Apply an ointment. Once you’ve drained the blister, you may notice that the overlying skin of the blister looks saggy. Don’t pick at this skin which could damage the blister and make the infection worse. Instead, leave the overlying skin as intact as possible. Apply an antibiotic ointment to the drained blister.
Cover the blister with a bandage. Since the wound is technically open, you need to apply a bandage. You could also tape a gauze pad onto the blister. Change the bandage or gauze pad every day so the blister has a chance to heal.
Always wash your hands before and after you change the dressing.
Remove the dressing daily before bathing, and allow the water to clean it out in the shower. Pat it dry after the shower and reapply the bandage.