Continuity mistake: When Tori joins the group during the final season, she and Zack date for two episodes, but they are not in sequential order.
Visible crew/equipment: After the fashion show when Zack says "Sorry Lisa, I don't know what to say" an entire boom microphone assembly is visible and snatched out of view at the top of the screen.
Continuity mistake: In the 1st season (the Ms. Bliss episodes), Zack mentioned to Screech in one episode that he had good news for Screech's brother. But in the Bayside episodes, Screech confirmed being an only child (specifically said in this episode).
School Song - S4-E24
Continuity mistake: Zack messes with the piano so it will give him a chance of winning. When Tori plays it sounds like she is messing up. But immediately following that screech plays the piano with no problem and there was no time to fix the piano.
Answer: Zack is always good for a sarcastic jibe. Lisa was written as the most fashion and make-up conscious of the Bayside High girls. She was also portrayed as serious and somewhat prissy. The "crack your makeup" comment was a throwaway line. Zack was suggesting Lisa doesn't often get overly excited for fear of having to reapply her face. The line is met by laughter and screeches from largely adolescent female audience that seem out of proportion to the humor. "Saved By the Bell" audiences were rather prone to such excessive ebullience for no apparent reason. The reaction didn't last long, and the scene moved on quickly.
Michael Albert
Yeah that doesn't make any sense.