Sorry, I just remembered I signed up for here! On some many ferret boards, its hard to keep track!BiBi is so young. How old is Bandit? He might already know not to bite, perhaps you got him from a breeder or somewhere he was previously handled? Is BiBi from the pet store? Often pet store ferrets are not taught that biting is not ok. They think you are just like any other ferret, tough skinned and ready for action!
I'm not sure what you are doing to try to get her to stop, but never flick them on the nose. That is extremely painful to them and only brings on the thoughts that biting and pain are ok. Their noses are sensitive and they need all those nerves to smell everything and find things. Just remember that!
Other ways to teach no biting: scruffing when they go to bite, flip them on their back, and gently drag about 1' along the floor. You are telling her you are Alpha, you are "dominating" her like other ferrets do with each other. Do this everytime. You might also want to say "NO BITE" in a loud stern voice to him while you scruff, look him in the eyes. Either wait til he yawns then cuddle him, do not put him down right away. Or go straight to the dragging (by the scruff) if this is like the 3rd or 4th time you have scruffed him for biting IN A ROW.
Lets say he's bitten you or just put his teeth on you, you must teach both are wrong first so he understands this. And you're just so frustrated! Try putting him in his carrier, alone, no toys no bedding. Then do 1 of two things, and stick to it: 1 stick him in another room, facing a wall and totally ignore him for 3-5mins (any longer and he will forget); 2 stick him in his carrier in the same room you are with Bandit. Play with Bandit in his full view and play nice, if Bandit nips at all this will not work. Do this for 3-5mins, ferrets hate to be ignored so soon hopefully he should learn biting is not play behavior with you.
Also try Fooey (Drs Foster and Smith website $5) a type of bitter spray, works great and stays on your skin a long time! Or bitter apple spray (cream if you can find it), doesn't work as well because some animals like the taste!
Keep handling him when he bites, if he bites for you to let go, DON'T! You are reinforcing the bad behavior. Do not pull away when he bites, push your hand/arm/foot/leg towards his mouth. This should force him to let go. Or stay completely still, don't say anything in pain or not (its the reaction he wants), instead scruff him to get him off you. Then drag, and whatever.
Hope this helps and you've been doing well training him!
I forgot to respond to the rest. Itching is not uncommon in ferrets. It usually means nothing, except an itch! My ferret will stop playing to itch something. Not a biggy. If they had fleas, you would know. There would be small red bumps on your arms after contact with him. So don't worry about that.You are sick, boyfriend is out of town. Yes, let them out of the cage. Don't cough or sneeze around them (if you can help it). Wash your hands before you pick them up, and cover your mouth if you need to cough/sneeze around them. Just common stuff you would do for people. May want to spend less time letting them near your face or directly snuggling with you. Otherwise, its just commonsense because they can pick up respiratory infections (like if they sniff dust from litter).