Dez is right, you are very strong for opening up! I know that fighting urges is hard, and it's not stupid for you to have them. After you've done it once it tends to occupy your mind all the time. However, they cannot control you, only you can control you. All it takes to resist a self-harm urge is the want to not do it followed by willpower. Try maybe doing something you enjoy, expressing yourself with music, words, or art, or even stretching or excerciseing. Sometimes when your body is filled with so much tension you just don't know what to do with it so you end up self-harming, but there are many ways to release this tension such as taking a warm bath, sitting down with your favourite snack and a good book, taking a nap, or, on the more physical side, stretching all of your body, running, dancing, screaming, etc. This is just a brief summary of things you can do, the list Dez sent you to has many more great suggestions!
I wish you the best of luck