Couple on Lover's Lane Witness Man Hanging Himself

by Jennifer
(Orion, Michigan, USA)

There was a late 70's / early 80's movie that I saw the beginning of at the drive-in with my parents when I was young.

All I can remember is the opening, where a couple is making out in a car, and the film cuts to a man going to a nearby tree and hanging himself.

For some reason, the girl sees the man and freaks out, starting to scream without end. Then she starts throwing up, eventually her own tongue and organs and blood, then rips her own face off.

My parents realized how the film was going (I was pretty young) and promptly left the drive-in. I have been looking for the title to this movie for over 20 years and this is all I saw of it. Please help!