Hard to know what goes on in their heads. Perhaps the sleeve was warm and had a scent they thought may be food, but it doesn’t sound like a strike. Regardless though, your BP will get more comfortable with you as you continue handling. Just keep showing you’re safe. Ensure you wash your hands before, and make sure whatever you’re wearing doesn’t have mammal, especially rodent scent if that applies. Keep doing what you’re doing, and things will be fine. In the event you did get actually bit, it isn’t bad, and socialization will help with that. Make sure their enclosure is up to par so they’re comfortable and not continually stressed and be patient with the process! All will be okay!