There's some info on what to do instead of hurting yourself at the top of the Self Injury forum.

I don't think I've ever let anyone watch me cut...I've always seemed to be super cautious when I'm cutting. I'm sure your dad is only doing what he thinks is right and healthy, but you need to do this for yourself, not him.

I'm not gonna tell you cutting isn't addictive, because it really is. I speak from experience. I guess you need to start telling yourself that you don't need to cut. Harder than it sounds, I know. Try telling yourself that first when you want to cut, then go try doing some physical activity or an activity that keeps your hands really busy.