I need some advice for some family revenge

So, my big sister has abused me emotionally and quite a few times phiscally, and I'm just tired of it. I want to call the cops on her but I'm scared that my mom will begin to abuse me out of sadness and anger, since she doesnt do anything except tell my sister to stop. I seriously want revenge, but I dont want to do anything that'll throw me in jail, even if it could possible be worth it. Unfortunately, I cant talk to my dad about this because my mom wont let me, and because he's working in a different state.

What do I do?