I am currently receiving Dialectical Behavior Therapy for my mental health issues. I've got a few coping mechanisms I could suggest to you. But first of all, I don't think that you're an asshole.
If you ever feel like self harming, you could go for a run or do some push ups, or stimulate your body somehow, get some sort of exercise. I know it's really hard to motivate yourself to do this but anything is better than hurting yourself. Go for a short sprint if you can. Put all your energy into it, get that energy out quickly.
You can also dunk your head/face briefly into a tub of cold water. It stimulates your body and provides distraction. This might sound silly.
One of the reasons I personally self-harm is due to overwhelming emotions. A lot of these emotions begin as thoughts. Try to take your thoughts for what they are, not every thought that enters your head is true. Look at the facts of the situation. Try to just observe your thought, and recognize that you had that thought. But don't believe every thought you have is a fact. This is also really difficult for me to do because my emotions overtake me at times. But when that happens, utilize coping mechanisms. Get creative with it. Anything that keeps you from hurting yourself or others.
If you have anyone to talk to that will listen, tell them how you feel. Just pour your heart out, I find that really helpful. Speak about your emotions. If you begin to feel the urge to self harm, reach out to someone you can trust if possible. Just talk to them, listen to their words. Let others try to help you. Just talk until you've calmed down a bit.
Do you have any hobbies? Honestly anything that keeps your hands busy long enough to not self harm. Personally, when I felt like cutting myself recently, I instead grabbed and book and cut it up instead. Those are just a few of many. Look into other coping mechanisms for yourself please.
Best of luck.