When I was a child I felt bullied by my sister and a few years ago I was sobbing in my therapists office about it and I didn't know how to feel better. I couldn't undo anything, i wasn't a child anymore. It wasn't fair! No the scriptures didn't help me either. You're right. She told me that I should consider forgiving her. I didn't know how at first. I felt so much pain about it still and when I tried to talk to her about it she just told me I was a whiny crybaby. I started reading about forgiveness and I started to try to see things from my sister's perspective and I found some empathy for her and I have forgiven her. She was just a child too and had gone through the same trauma as me and took it out on me. (And this is not the same as you, I was just sharing some of my journey.)
I don't think we can ever know why things happen. We can trace our trauma to people and they have their trauma which caused them to hurt others and the cycle goes back and back and back. We just have to stop the cycle of abuse and try not to hurt others. That's all I can think to do....