Can someone hex you if you don’t deserve it?

If you didn’t practise any witch craft or protection and someone went out of their way to hex you without any reason to, could they do it with no bad energy returned? Or would it back fire and give them their bad karma ?

I have done nothing wrong to this person, I suppose the only thing I did wrong in her eyes was fall pregnant to her ex (they weren’t together at the time, but got shortly back together a couple months after a fell pregnant… I had no idea she existed or he had an ex when I was involved with my baby daddy). I kept the baby and just had the baby and she’s been body shaming me, insulting my baby and talking badly about me to other people. I think she is into witch craft and is actually a complete nut case …. Has said that she wants to set me on fire and insulted my baby.

Does anyone know what I can particularly do in this situation and if she did hex me or send me negative energy… would it backfire considering I have done absolutely nothing negative to her ?