This is a topic that has been talked about for years, some doctors suggest doing it other say leave the pimple alone and just use medication on it. Personally, I think squeezing a pimple can be good as long as you do it the right way.  If you leave the pimple it can lead to scarring and uneven skin from my experience.  Squeezing the pimple can quicken the healing process.

First make sure your are prepared. Get some acne medication, clean towel, soap, and two clean pieces of soft tissue paper. I recommend doing this at night after a warm shower when your pores are opened up. Also, this is for people who only have moderate acne(only a few pimples every few weeks).  If you have really bad acne, please consult a Doctor.

If you haven't washed your face and hands, please do so. If you are coming out of the shower you are ok!  Put a piece of tissue in each hand, grip it so you can squeeze the pimple. Squeeze softly around the pimple, it shouldn't take much pressure. Don't apply to much or you can bruise the sking around the pimple.

After it pops, make sure the juice doesn't get on any other part of your skin so it doesn't spread. Then wash pimple area with acne soap and water. You can use an acne cleaner if you have one like "Revitalizing Toner," by Proactiv. This will clean out the skin area if there is any juice or dirt left.

Then pat your affected area with a Towel and apply the acne cream on lightly. Now your are done.