What should I do about my mum not letting me see my girlfriend?

So, for those of you that don’t already know I’ve been going out with this girl same age as me, and my mums never really liked her. She used to be a bit controlling and stuff and I’d ask tk her to like bite me and do other stuff to me, although I bruise easily she said no but eventually gave in. A few months back, everyone had been getting the wrong idea about my girlfriend, saying that she never got a bath, she’d beat me up, use and abuse me, make me go a whole day without food by using my dinner money to buy things that she needed. None of what people say about her was true except the fact I werent allowed to see or talk to my friends witgout getting a ‘you fancy him/her’. So, a few months ago, when she came to my house coz we was gunna go to hers for tea, my mum said she has had enough of me being abused anf beaten up, having to go ages with dinner, and said if my girlfriend got help we’d be able to talk. Ever since, I’ve been getting into trouble for talking to my girlfriend, I can see the change in her. One time i went round with her in school and when i got home my mum squeezed my throat and hit me on the side of my head. I want to stay with this girl eveb though my mum says I cant etc… but we love each other, I dont think my mum wants to ‘see’ all the bad things I’ve done to this girl. I just dont know what to do. Any opinions? Thanks