My glider is female 1 and 1/2 years old, I adopted her from a very caring family who said she came from an abusive situation where she was fed only pellet food and in a small cage. She also has a big mating wound scar on her back and the fur is starting to grow back.
Animals remember. So if this critter has an abusive history, she's essentially broken. That doesnt mean she is worthless, it just becomes a problem that some effort and time might resolve or perhaps never resolve. What I do with sugar gliders like this is find them a cage mate who likes human attention. This lets them see what healthy interaction can look like and sometimes they come around and begin to compete for attention.
In the end, so what if it bites you. What were you hoping for in the beginning anyway? I think it is possible to tame this one up some but she may never be a trusting animal and you just have to find a way to live with that. A cage mate is a good start. Endless patience and never giving up is another.
I like to present a finger then a treat. ie: put a treat between your fingers, then lightly bump the nose with top of finger/knuckle and then immediately present treat. The critter should choose the treat over your finger and the more you do that the more it will associate a treat with the same image it had of biting and hopefully the treat will eventually replace the biting. So then later when she senses a finger, she will look for a treat instead of going for flesh.
Just think of creative things to do, and in the end, it is about repetition. It takes a LOT of effort to write over previous programming.