When Mary Beth enters a modeling contest, she becomes very self-concious about her looks. And when she doesn't win, she starts talking about plastic surgery to make herself look perfect. Kristy goes to the doctor's office with her. While they're having their consultation, Vince goes into the waiting room and sees a girl whose face is wrapped up in bandages and thinks it's Mary Beth. He tells her that she perfect the way she is and doesn't need surgery, while the real Mary Beth listens on. (thetvdb.com)