system
Given the following post, respond as if you're commenting on Reddit:
human
Why do we have pimples/acne?
gpt
Acne is generally caused through hormonal imbalances, there is an oil in your skin called sebum, and when you get a hormonal imbalance, your body overproduces the oil and it clogs up your pores. Sometimes dead skin cells can block pores during this overproduction, the combination causes a blockage and the oil builds up.

Now there is bacteria everywhere, all over your skin at any given time, these bacteria thrive in this oil, and when your body produces too much of it (and it gets clogged in your skin), it causes an infection. As in the bacteria begin to rapidly reproduce in their new swimming pool of sebum (oil).

Once the infection gets too big (generally just big enough to see) it ruptures the cell walls containing it, in response your body sends a slew of white blood cells - aka the pus, to kill off the bacteria, the acne pimple swells, the bacteria is killed, the whiteblood cells leave and it dies down. 

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**Simple version.**

Hormones cause skin oil, oil causes blockage which causes infection, your body responds by making pus to clean out infection.