system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do pimple patches suck the puss out even before the pimple emerges?

I put a pimple patch on a pimple that was still emerging because it was getting HUGE and I read that the patches can decrease the swelling. I took the patch off a few hours later and the swelling had reduced and there was some puss on the patch. How?
gpt
Most pacthes use a very mild acid to break down skin oils like those that clog pores.  Your pimple was probably close to draining, but the pressure made it uncomfortable, as the acid worked away at the clog, the discharge was able to drain, relieving the pressure without having to painfully squeeze it.