You can if you are being very careful. If you burst the blisters in the same way a doctor would do it with "normal" blisters, basically use a clean sharp needle. Many PPP sufferers find relief bursting the blisters as the skin around the outbreak won't be as tight and the itch will be reduced. But be very careful if you plan to do this so you don't get an infection. I personally would advise not to do it.