How to make my mother believe?

Ohk, I had written on this website some time in November about my moms boyfriend. It was about how he was being very inappropriate towards me and what to do about it. Well one day I flipped while my mom was at work and it was just me and him in my house. He was yelling at me for stupid stuff like he usually does and I got so frustrated that I just started calling him a perv. I said “ I went on for almost a year without saying anything you’ve done to me and I can’t take it nomore. “ He stood there and said “ what ? Why would I do that to you ? Maybe it’s all in your head. “ I was just about ready to kill him for trying to make it look like I made it up in my head or something. So I called my mom and told her mostly everything and he denied it and she refused to come home from work when I asked her to. I actually started crying. I said to her “ after what I just told you you’re not going to come home ? What kind of mother are you ? I just told you your boyfriends a perv and you’re not coming home ? “ He said I pulled the story out my butt just to get him kicked out and crap like that. He was packing to leave the whole time and I broke my stand up mirror. I actually cut my wrist about three times with a piece of broken glass just to see if I would feel better. This was two months ago. My mom doesn’t believe me obviously because she’s still with him. He lives with his mom and my mom spends most of her time with him now. He occasionally sleeps over my house and I can’t do anything about it. I was sooo close to my mom and still am and that’s why it hurts me so much that she’s still with him and spends most of her time with him. She still likes to spend time with me but he always gets mad at her if she ant spend time with him so that’s why she’s with him a lot. He calls her every two seconds when she’s not with him and asks about her every move. It is actually mother’s day today and the whole day she’s been with him. I said to him “ it’s mother’s day, go spend it with YOUR own mother and not mine “ and he was just like whatever. I cry a lot whenever my mom says bye to me when she’s going to his moms house to be with him because I just want my mommie back. She is my bestfriend and I miss mainly having her to myself.