friend chooses her boyfriend over me

long story short, my mum told my best friends mum that she has underage sex with her boyfriend (she’s 14 he’s 16) so now he’s not allowed round her house. so yesterday at lunch my best friend went to see her teacher about something and her boyfriend screamed in my face and made me cry in front of all our friends about how it was my fault and i should have kept my mouth shut. (nobody even likes him because he’s abusive and controlling towards us and my friend) since my friend wasn’t there, she didn’t know about it until my friends told her after school. they told her the true but her boyfriend told her a different story, which i think she believed. all my friends, even the ones that weren’t there, called me to ask if i was ok apart from my supposed “best friend”.

today she didn’t speak to me at all and was all over her boyfriend (literally wouldn’t leave his side and constantly making out with him) she never asked me if i was ok and it’s left me really worried about our friendship because she’s only known this boy for 5 months and we have a 6 year friendship, and she always told me that i come before him but clearly this isn’t the case.

if it was my boyfriend doing that to her, i would have rushed to her and asked her if she was ok and told her i’d never let him do that again, and then i would go to him and have a serious talk about the way he treats my friends.

i don’t know if this is just me, but i’m sick of her putting him before me, that shouldn’t happen right?

advice on what to do? should i try to talk to her or is that her job since it was her boyfriend?

thank you all help is appreciated