Unintentionally, I found a really good looking manga whilst searching for some Ibuki Satsuki wallpaper. I only saw parts (or rather, pages) of the manga since I was on Google Images. I was planning to look more into it and possibly read it, but I "lost all trace of it". It isn't in my history since I was on private browsing. So if you know what this manga could possibly be, please tell me! Thanks!!!

I know that the genre of the manga is horror.
I believe the title starts with an M or at least has one somewhere.

When looking at the various images, I saw:
*a girl with long dark (most likely black) hair; she seems to be the heroine or a very important character
*there was a killer nurse (had light colored and short hair)
*there were many "patients" (I guess) strapped down to be tortured by the nurse
*I remember specifically that one of the patients was a young girl who was getting her forehead sliced (opened??)

That's all I recall. I spent 3 days searching, so ANY help will be greatly appreciated.