You will be arrested and sent to jail where you would stay until your court date unless someone posts bond. The judge can sentence you to a hospital if they find that you were out of your mind at the time of the assault but that is highly unlikely especially since you aren't psychotic and knew what you were doing.

This is a lot darker, but to put it in perspective...there is a woman who was abused and tortured her entire life by her mother who had Munchasen's by proxy. She ended up killing her because she saw no other way out. No one doubts that this literally made her go insane...but she's now serving a sentence in PRISON, not a mental hospital.

We are still accountable for our actions.

PS hurting yourself alone does not get you hospitalized. Especially for most insurance to pay for it they have to have reason to believe your life is in danger.