Yes, I'd say you need to forgive that alter - she is part of you and you are part of her. Most likely she has been trained by her abusers to continue on what they began. See her as victimized and needing to learn proper self-care. She needs to learn how to handle her feelings and fears and anger. She can learn that from other parts of you and from your T if you have one.

I've had some fights with parts of myself that were hostile to each other and needed to learn that we can't take our feelings out on other parts - it is not their fault, its the abusers faults.

Hope you two can communicate and get closer.

Leslie and the pixies