Congrats on your new baby and welcome to GG!
Ok, so you have a newby who is very scared and alone.
He needs to build trust with you both and it takes time and a lot of patience.
Have you been doing the fleece blankies with your scents on them? You can take some 5" x 5" squares and sleep with them in your pillow case or wear them tucked in your clothes, and then each day give him a new one in his sleeping pouch that smells like you.
Usually the first week...it is good to let them settle in. Talk to him when ever you approach his cage. Sit by his cage and talk to him...if he comes to greet you...offer a treat.
Don't try to grab him unless absolutely necessary. Have a pouch or large square piece of fleece so he doesn't associate your hands with being grabbed by a predator.
When I take my gliders out of the cage I take the whole sleeping pouch so I don't have to reach my hand in over their heads.
Are you getting him a buddy? That will also help with his confidence and his loneliness. They will also actually bond quicker if they have a buddy.
A person cannot provide the kind of companionship a glider needs. They are colony animals and do best in pairs(or more). They need someone to eat, sleep and play with and to help them groom themselves.
The other thing with the biting is that gliders go thru a "toddler, terrible 2's" type of nippy stage and will taste or bite pretty much anything. They are testing you for one, and using their instinct to bite harder to puncture thru bark and draw out more sap...except its your fingers.
When he looks like he is going to bite(look for the signs...there are always warnings)and distract him with a toy and/or a PSSSTTTT noise. That is what gliders do to tell another one they are annoyed...and to knock it off.
Keep scented soaps and lotions to a minimum. That way he won't have to taste you to see if your edible.
Just take it slow and go at his pace.