You are making the major mistake of trying to push her into trusting you.
LEAVE HER ALONE, she's fear biting. She needs to be left alone until SHE comes to you - this is not done in 2 months with some dogs, especially ones that have been abused.
Every time you touch her or try to hold her, it reinforces her fears. She is HAND SHY -- don't touch her unless it's her idea to come to you - that will happen in due time, but at her rate, not yours.
Don't "cuddle her", don't put your hand in her face or anywhere near her.
I've had 2 dogs like this, one so traumatized she hid under the bed for 5 months, was a year before we could pet her and longer before she finally decided to come on lap for pets. She's o.k. now, very loving, but will never be totally trusting with everyone.
Last year I took in another fear biter - had bitten 7 people. I left her alone, just let her realize she was safe and did not need to defend herself. I never picked her up or tried to cuddle her.
After a year, she's the first one on the couch next to me, but I still have to lure her into her crate at night with some liverwurst on a plate in front of her and say "come, on, let's go beddy byes" - she comes eventually,g ets the liverwurst treat when she's in the crate.
She now sits on my lap, but I still have to block my other dogs with a hand or foot in front of her when she eats a treat - and I don't pick her up when she has herself pressed against a wall - that's her fear, being cornered and having things taken away from her.
She gets better all the time, a little doll, very spunky, but she had to be a fear biter in order to survive in the miserable place she used to live.
Have patience, let her come to you, don't touch, don't push her --- just provide the food, speak calmly, NEVER SHOUT AT HER or get angry, that just sets her back to when she was hurt by angry humans --- don't yell at her, worst thing you can do.
Take it easy, let her come on her time --- can take much longer than 2 months, but will be worth it when she trusts you and no longer needs to fear you.
I'm glad you took this scared, abused dog in and want to give her a good forever home --- wish there were more people with your kindness and empathy.