Contrary to popular belief poison ivy is only spread by the oil from the plant and not popped blisters. Blisters are the bodies reaction to the oil. You may notice additional blisters as time goes by but the original blisters are where you got most of the oil on you to begin with. I've had poison ivy 3 times in my life. In junior high and twice as an adult. Yes once on the penis and made a beeline to the doctor. Each time i was infected was less severe than the preceding times. First time was tablets dissolved in water to dab on me. What a joke. All other times i was given steroid pills. The time on the penis i was given a shot. One of the very few times the needle was my friend. Lol.