Of course my gliders have bitten me in defense, but the past few days one of my gliders has been acting different.

One of my gliders, Titania, is warming up to me a lot. When she hears me enter the room and she's awake sometimes she'll wait for a treat from me. And a lot of the time, she jumps onto me from the cage whenever I open it. She also chooses to jump and climb on me when I let her roam my room a bit instead of somewhere else, but she's been increasingly biting me more and more, and it really hurts. She bites my fingernails, my hair, my eyelashes, my ears, and my earrings. Most of the time it really hurts, and I'm worried she could try and rip out my earring. The other day she bit my thumb and I bled a little bit. I try to gently hiss at her to tell her that I don't like what she's doing, but she refuses to stop. It's never seemed aggressive or anything, but I can't seem to make her stop.

She chews on and tries to eat almost everything she sees, but normally, she doesn't do that to me.

I'm just unsure of what to do about this behavior and what it means. I've considered it to be grooming? But she is biting a lot harder than I would've expected for grooming. Any help on this would be great. She's never done anything like this before until very recently.^^

Yes, it is considered grooming. The majority of bites (by the way you describe them) sound just like your glider is grooming you. The best thing to do is to not jerk away and make the hissing sound if it gets too bad. Slowly pull away your hand out of her reach if she is hurting it. It could also be her testing you to see what she can get away with.