I have a rather large blood blister on my stomach area and it started bleeding so i popped it. how can i now prevent infection?

Blood blister: Generally, blisters should not be "popped" as the area beneath them is sterile. Preventive measure for one you've broken: wash gently with warm soap & water; pat dry; apply antibiotic ointment & non-stick bandage. Watch for signs of infection: pain, increasing redness, pus. If those occur, see doc for treatment. Btw, may not have been blood blister: as we age get benign red lumps called hemangioma.