You really shouldn't. Is there really no other way?
There's no wrong in feeling pain nor the thoughts of depression but it is wrong to surrender to the depression and pain that tortured you.
Why not leave it as it it? Endure through the pain and when time starts to heal, you'll be laughing and enjoying the win.
Pain are like rain: It showers you and make you cold and after a long, lonely shower. It disappears and the sun rise again making you feel warm.
Cutting yourself, feeling depressed, everything you're doing that is making yourself hurt more. I don't know why you're doing this to make a memory of depression. Scars are something that stays forever, they'll remind you of the depression even if you have gone past it. Don't be so stupid, and let people help.
People are out there watching life past by, but why is it that people like them have to suffer a sudden chill when they hear you're hurt when all they always see are smiles?
Give it a thought, people are out there looking after you, loving you when you're not, caring for you more than you're caring for yourself, and feeling scared for you because you aren't doing it yourself.
Think about them, think about you.
I know it's painful but pain won't last and scars will.