A Thousand Little Cuts (1969) on Netflix

A young woman wakes up in a hospital, convinced she is recovering from minor surgery only to find herself in a battle of wits with a psychiatrist who can't let her leave until she remembers "what happened that night." Events turn a darker corner as doctor and patient try to unlock not only what traumatic event Anne is suppressing, but also who was there, why it happened, and why Anne's subconscious is fighting so hard to prevent her from talking about it.