Learn how to care for a bad pimple and problem skin.  This is what to do if you get a painful pimple. 
 
When a pimple is forming under your skin you will usually feel pain or itching in the area.  It may become a bit red and large.  At this stage the best thing to do is warm compresses.  By putting a warm compress (i.e. a warm wash cloth)  you encourage the pimple to come to a head where it will have a white top.  At this point you can gently evacuate the pimple.  Do not use fingernails or sharp objects.  The most common cause of scarring is from using sharp objects or forcing out the pimple before it is ready.  Scars can be hard to fix so be sure to use a warm compress and wait for it to be ready.  If you are having difficulty you should consult with a dermatologist.