Jan,
 
From your description, my guess is that Zachary really thinks you are
playing when you do things to stop him from biting, and just hasn't been
able to get it through his "wild and crazy" head that he is hurting you.
Since he has a strong bond with you, I think your challenge is to get him
to understand that he is causing you pain.
 
I had a similar situation with my Alfalfa (also a silver mitt,
coincidentally).  For the first two or three years of his life (I got him
as a kit), he would go for any exposed flesh, just as you describe.  He
didn't bite hard enough to break the skin, but it did hurt!  What seemed
to help - although it took a long time - is to do what came naturally:
SCREAM!  LOUDLY!  This startled him, and definitely made an impression.
He would stop what he was doing and just stare at my face.  Whether he
finally understood that he was causing me pain, or whether my "unpleasant"
noise was simply negative reinforcement for undesirable behavior, I'm not
sure.  But by the time he was about three, he had completely stopped biting
and became the sweetest, kissiest ferret.  He's now six, and my neighbor
kids regularly play with him and my five others.  They all love "Big Al."
 
He still terrorizes my cat though, poor kitty...
 
Nancy and critters
[Posted in FML issue 3485]