How does anorexia nervosa affect the body? why does is anorexia so dangerous?

Anorexia Nervosa is so dangerous. The scary thing about this mental illness is that like many, it can go undiagnosed. It causes the human brain to turn against its self, and hate the thing that it needs most to survive. It can cause overexercising, even when hurt, hair loss, fainting episodes, extreme weight loss, coldness, weak immune system. And those are just to name a few. Anorexia is something that people can hide, and that they think is normal, even to a point where it's too late. This illness is no joke.

depends where it is? i got mine on my arm and from 1-10 it was a 3 different spots react differently