Any possibility you could change cages for her? Is she still in the cage she was attacked in?
I had a pair of cockatiel babies, a brother (Jessie), and a sister (Tasha). They were kept in the same cage and were being hand tamed by a friend. When they became sexually mature, the brother suddenly plucked his sister bare of about 80% of her feathers and left her bloody and beaten on the floor of the cage. I immediately took Jessie out of the cage and Tasha to the vet. Vet said the cock bird wanted to mate and the hen refused and the cock beat her because she could not get away from him in the cage.
I left the cock bird with my friend for more hand training and took Tasha home; again I kept her in the cage she had shared with Jessie: thinking she would be more comfortable in a cage she thought of as home. Tasha would not eat, would not move around the cage and cowered in the bottom of the cage all the time. After three days I called the vet. Dr Stern recommended putting her in a different cage, placing all food and water on the floor and covering the back and two sides of the cage as well as the top. Within 12 hours Tasha began eating and subsequently recovered completely... Except she never felt comfortable around any cock bird ever again for the thirteen years she lived. I had to keep her in with two other hens and never with a cock; if I put a cock in the cage with her, she plucked herself bare and stopped eating. Tasha was an egg factory; she laid at least one egg a month, mating season or not: and she sat on them constantly throughout her entire life.
I think she was happy. She enjoyed playing mom with her eggs and interacting with her two half-sisters. She liked people and liked to sit on my head after getting her treat for the day. I miss Tasha now she is gone; she was a gentle soul.