system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does oily skin cause acne on face?

Can someone please explain the process of pimples forming that is caused by oil to me?
gpt
The oils block up your pores in the skin.  They build up more secretions behind it, including bacteria and various other lipids and fluids.  The raised tension behind the buildup causes the visible red bump of the pimple.