Obsessive Lip Balm User Kills Older Sister in 90's Film

by Anonymous

There's a horror film I saw in the 90's about a hot girl that kills her older sister.

I believe it's someone who works for her family that figures out she's the killer. The worker also looks a lot like the dead sister.

The worker tricks the killer into thinking her sister's ghost is haunting her. This leads to a struggle and they try to kill each other.

At one point in the film, the worker is sent to a mental institution. But in the end, the killer is institutionalized.

Also the killer has this habit throughout the movie of using lip balm.

I need to figure out this movie title! Help!