Who hasn't spend time in front of a magnifying mirror & 1/2 hour later wondered what possessed you to squeeze your pores as if your waiting for Mount Vesuvius to re-erupt. Unfortunately, your causing more damage to your skin than what you think was initially there. That blackhead or pimple which hasn't come to a head is not going to disappear once you've attacked their territory. But for most the satisfaction of squeezing or picking at your skin out weighs the outcome. I'm not a dermatologist nor imply that I am, therefore I won't go into the ramifications of touching your skin or repeat other sources, since the links I'll post are great sources no need to go into further detail.
Have a look & let me know what your thoughts are on the matter & if you are a skin picker/squeezer?
Although the above sites are focused on picking, I do believe that squeezing can lead to picking. In other words put that magnifying mirror away!