Assess the popping situation. Only pimples with pus, known as a whitehead, can be popped. Trying to coax some ooze out of an under the skin blemish is very painful and will leave a scar.
Wash your face and hands.
Steam open your pores. This can be done in the shower, applying a hot wet washcloth compress (heated in the microwave works well) for a few minutes or holding the face over a pot of steaming water for a few minutes.
Wipe the area with gauze or cotton ball soaked with rubbing alcohol or hydrogen peroxide. The pimple may be seeping by this point or completely popped.
Wrap both index fingers with gauze or tissue. Using the fingers and looking in a magnifying mirror, apply pressure with fingers pushing down on either side of the pimple causing the pus to pop up and out. Alternatively, an extractor, an instrument with two loops on either end similar in size to an eyebrow tweezer (available at beauty supply stores), can be used to apply pressure.
Apply more pressure if pus remains. If that doesn't work, steam your face again and repeat process. (The washcloth in the microwave is the most expedient method.) A sterilized tweezers is handy to pull out remaining pus, as sometimes it is hard or string like.
Check to make sure all the pus is gone. There will be a hole or a red (blood) dot. Wipe area with rubbing alcohol or hydrogen peroxide.
Place an ice cube on the now former whitehead. This closes the pores.
Apply a small amount of Vitamin E on spot to prevent scarring. Make daily Vitamin E applications until healed