Is she angry (quills up, huffing) when she bites, or does she seem happy beforehand? Does she lick before biting? If she's being grumpy I'll be she's uncomfortable from quilling. If she has her quills down and bites for the heck of it, well, hedgies have lots of reasons they do that. Make sure you don't put her directly back into her cage, she'll learn that biting gets you to leave her alone. If she's licking, know that a bite is coming and move your hand out of the way.