I m trying to remember the title of a movie that was aired in france in the late 80s or beginning 90s, I think it was american or australian.

2 scenes I remember:

• shower scene: an “attractive blonde woman” showering with a man (victim) she changed into an ugly scary/burnt woman. when i was a kid, I used to call her the Purple woman because her face and body has bruises and was kinda violet/blue. I think she ends up stabbing him, I remember blood falling…
• I remember outdoor scenes as well
• public space scene: A woman (a victim) finds her boy friend sitting in a public space (he was waiting for her) and when she tried to call his name, he wouldn’t answer, at some point she touched his head and saw that a knife was on his throat…she screams.

That’s all I remember, anyone recalling something?

thanks