I have only a vague description about this 90s or 2000s movie. I am sure the movie plot itself was so confusing.
I think there are two female lead characters and the film is happening in Hollywood.
One is a wannabe actress and the other one is an established actress (not sure).
In the beginning of the film, one of the lead actresses met with an accident and got the help of the other. I think she lost her memory too.
The two actresses seems to be in love with each other and one becomes missing. The other looks for her and finds her decomposing dead body and recollected that she killed her. Also she had some mental problem and she was not who she assumed she was. She switched her character with the other actress. She killed herself because she indicated breaking up with her.
I am sure it was a critically well acclaimed movie and that was the reason I watched that 4-5 years ago.