[cypher]

What's his cage set up like? If you have a photo it would help to see if there are any changes that might help him feel more settled, secure & confident.
Too much open space, not enough substrate to burrow in, lack of a good sized house with no base on a deep layer of substrate to burrow down in are some of the things that can prevent them from feeling safe in the cage but it would help to see what you have.
What wheel does he have?
I would avoid any attempts to interact with him in the cage for now, if you can put food & water in when he's sleeping.
See if you can get him to climb into something you can transport him in then take him to a safe play area, a playpen you can sit in with him is a good way to begin to get him used to handling & he may be less inclined to bite away from the cage.
Put toys, tubes, things to explore in the play area too.
Just short sessions to begin with so he doesn't get stressed.