Season 1: Episode 8: Cream for a Day
Kelly's dreams come true when she is nominated for homecoming queen, but a zit on the end of her nose sends Kelly into frantic mode. Kelly locks herself in her room because she's so ashamed of her little blemish. Meanwhile, Zack and Screech accidentally invent a cream in chemistry class that clears up acne. Of course, Zack is all about making the big bucks, so he and Screech start selling the acne cream at school. There's only one problem, it turns everyone's face maroon.