Fever blisters should not be popped they should be allowed to heal naturally but you can use products to speed up recovery. Popping them will only further irritate them and could cause infection in other places if the bacteria from the blister gets in anything else. If you have a fever blister try cleaning it with peroxide and alcohol and also if you want to get rid of it quickly use nail polish
. remover to dry it out and use ice to stop the swelling. You can also use Neosporen to ensure you don't have any scratches but doing so will create a scab that could take some time to heal.
