Acne is formed when the pore gets blocked and the oil or sebum is trapped in the pore. The sebum getting trapped creates a perfect environment for the acne bacteria to survive. Once infected the pore swells up to create a red bump. So what causes the pore to get blocked? Well, dead skin cells. So why is it that your dead skin cells hang around on your face while those of your clear skinned friend don’t? That’s because in acne prone skin cell turnover is not efficient. Acne-prone skin produces more dead skin cells than normal skin, and these cells are not shed properly. They tend to stick to the surface of the skin. In normal skin, excess dead skin cells are constantly being sloughed away on their own.