No, it isn't good 'as long as there's no permanent damage' because there's still the memory that you even did it. You should look more closely at your signature... If nobody believes in you, at least you believe in yourself. If other people don't care, then that's their problem and they can deal with their own jadededness. I used to Self-Harm too and it was always good for those few seconds that I felt the pain, but then the emotion would always come right back. Self-harm won't solve anything. It only gives false hope and eventually downfall.
It's like doing drugs or drinking... everything's okay for those few minutes, but it all comes back eventually. And it tends to make things bad for others. You can't hide from it, so you have to confront it eventually. Confront it and then leave it behind because it's in the past. Your actions effect not only you, but other people, too. Someone could see that you're hurt and become depressed... and then their friends become depressed because they don't why they're upset and on and on.
Hold your head up, girl.
PM me if you want to talk more about it.