It is by no means unusual for teenagers to become depressed when pimples break out on their skin, especially on their faces. The feeling they suffer from is that they are ugly, and they are unable to join in with normal social activities with their friends. As a result of the frustration that this engenders, they are often driven to try almost anything that promises to remove the pimples. One of the cheapest, easiest, but unfortunately also one of the least successful strategies, is to try popping the pimples with their fingernails. The feeling seems to be that once the pimple is ruptured, it will go away.
But that is only true if it is popped cleanly and hygienically. Which is something that cannot happen when it is popped using fingernails, because fingernails are impossible to clean to the point of being sterile. As a result, instead of reducing the swelling, the operation tends to increase it, because the damaged skin is invaded by infection from the fingers.
Anyone who wants to know how to reduce pimple swelling would be far better off investing in a proper stainless steel pimple popper. Cheap to buy and easy to use, a good pimple popper can be sterilised easily by boiling it, and then used safely to pop the pimples. Afterwards, apply ice for a few minutes, and clean thoroughly with antiseptic. The skin will heal quickly, and the swelling will go down.