[header] How to treat a blood blister [title] Remove pressure from the blood blister. [step] Start by eliminating any pressure and exposing the blister to the air. You want to make sure nothing rubs against it, or presses down on it. 
Exposing it to the air allows it to start healing naturally. If it is not under any pressure, it will stay intact and the chances of it tearing or bursting and becoming infected are lessened.