I’m trying to identify a manga/anime/game/comic, these are the clues:
- Protagonist suffered some kind of head injury during an accident.
- He saw humans including his own friends look like monsters.
- He saw his environment (house, wall, chair, floor) looked like a bloody (red) organic disgusting mess.
- Suddenly a little girl that appeared normal and only this girl looked normal.
- He fell in love with the girl, and he become abhorrent of his own friends due to their appearance to him.
- The girl in reality is the monster, who looked not even humanoid but some kind of moving flesh with tentacles.