Whenever you get the urge, take two ice cubes in your fists and squeeze them as hard as you can. You can also draw things on your arms, like butterflies or hearts or puppies, etc. Or, you can even just skip straight to the bandaging. Rather than hurting yourself, just take some bandaids and put them wherever. Personally, my urge to self harm isn’t to “distract” myself or whatever - I just want to see myself getting injured. So I use a rubber band that I snap against my wrist until it welts and bruises. Please, though, try those other methods first.