I've Got You Under My Skin

Phoebe meets a photographer who turns out to be a demon who sucks the youth out of young women in order to remain young. While Pheobe is with him, Piper sees her friend Brittany Renolds, who is now elderly and has a poor memory after being attacked by the photographer. Brittany recognizes the address of the photographer, allowing Prue and Piper to arrive in time to vanquish the demon and reverse the damage it had done.