Definition of "zit"

I can't help thinking how little good all that working out did him. I think the only thing he ever got out of it was more zits.

1968, J. Lawrence Hagen, “Pinball 1959”, in Generation, volumes 20-21, page 182

Brad: Sara, did you take my Clearasil again? Sara: I ran out of brown (paint). Brad: Great. How am I supposed to cover up my zits?

1987 Adventures in Babysitting, 00:06:35