I hurt myself last night.
Why did you hurt yourself?
I was stressed about a break up and it made me feel better.
Hurting yourself is not a healthy way to get through pain. It's okay to ask someone, like a therapist, for help so you can learn to feel better without causing yourself physical pain.
Why not, it helped me last night.
You shouldn't view that as helping you out, because in the end it does nothing for you but make you think it's right for you to do that. It's going to be beneficial for you to seek therapy to help reduce your stress.