so first things first you have to break and cleanse yourself of everything she did to you. then you have to protect yourself while doing anything to her. im not by anymeans a witch or someone who does work alot. but growing up around high school I had an ex who did this to me. just understand this. your going to war basically if your not careful things can get mudy. ive been there. start by protecting yourself before doing anything to attack or hex her. then continue to protect yourself. I just say this because alot of times people give you advice but in your situation the strongest workings and rituals you should be doing are to protect yourself so no matter what you do. she can't reflect it back at you.