To start, I don't think the white nun will be bad - totally. We know from last year's Murder House adventure that Mr. Murphy is not going to settle for one bad guy. You all remember Hayden? Constance? Hell, even the dentist was a baddie. So, Bloody Face is not the only one just like the Rubber Man/Tate wasn't. Yeah, really... some kind of bad with an agenda and perhaps dead.
Now we know this is a mental hospital - thus the tag line American Horror Story: Asylum. Get Committed, plus we were told. And it is an accept practice of nuns who are also nurses to wear an all white outfit along with a white habit. So, she's a nurse, or was a nurse when she lived. Could she have been under the head nurses rule and somehow wronged her? Could the Monsieur or head Priest done something... the layered possibilities are enormous!
She could also be a novitiate sisters, one who is completing her vows and working towards becoming a sister. She's pretty, young and as someone who we would think would be naive, she could have befallen a fate worse then death and then killed herself? Hey! one can reach as far as one wants - and I still probably won't reach half as far as that mastermind Murphy.
Well here are some videos of her, let me hear what you are thinking!