Don't pop anything!Pressure blisters are caused from movement / pressure on your piercing as its trying to heal.Example : Helix piercing, its very common to get a pressure blister on your ear with this piercing because the bar we pierce with is 10mm in length and the bar tends to get moved in and out or knocked around with (Some people make the mistake of twisting their piercing like with an ear lobe) .Every time the bar moves or twists in the ear, its cutting the cartilage thats trying to heal itself, therefore a pressure blister forms because the wound trys to heal itself over the piercing.Its so simple to get rid of!You need to go and buy some aspro - clear (the aspirin that dissolves in water) , hold it in your palm sprinkle a few drops of water on it and it will start to fizz up a little bit, get a cotton tip and rub some around your piercing.You can do this 5/6 times a day or even more if you wanted to because it puts all the natural anti oxidants back into the piercing wound. Only continue cleaning with your antiseptics twice a day. Remember cleaning it to much is actually worse then not cleaning it at all!
Use a very fine pin to puncture it especially if it has liquid and drain as much of the liquid as possible some may disagree but it worked for me,please take into consideration I have skin that heals very well.
Try popping the blister and putting ice on it.