Woah woah uhm there are a lot of other things you can do!

-run. run and don't stop until you're legs are going to fall over
-use ice instead of a blade--it has a similar sting and isn't permanent
-use a rubberband and smack it into yourself on your wrist or leg
-take a pen (or pen cap) and scratch it out.
-keep your hands busy via papercrafts or sunflowerseed eating or stressball smushing
-and also play loud music and sing along--it helps make your mind busy

You can do it!