Heather - Sandy's absolutely right and explained it beautifully.
At 4 months old it shouldn't be too hard to get her under control. Have you tried grabbing her cheeks, lifting her front off the ground and forcing her to be still?
Don't let her go too soon - really hold her there until she calms down. It might take 30 seconds and it might take 2 minutes. Whatever you do, don't let her go while she's still squirming and struggling (or "wrinkling" her face
).
If you do, you're just empowering her dominant attitude by teaching her that if she fights hard and long enough, that she'll win.
Of course you need the right "attitude" along with the correction for the pup to respect your authority (what Sandy said). You may have to change the way you live with the puppy (make sure everything is done on YOUR terms, not hers and control everything she does).
Ban her from the furniture, from the bedroom, the kitchen etc. if you haven't already (those should only be earned privileges for a well-behaved dog). Don't give her free access to food or toys - make sure she realizes that everything comes from you.
In fact, don't give her free affection anymore. Make her earn everything she gets from you. Act aloof and superior around her and only give her food, affection, toys when she does something for you (sit or lie down or come on command).
Always have her on leash inside the home and supervize her - if you're not there to watch her, crate her.
Obviously, she should always be on leash when outdoors. A long-line works great for that. It's amazing how the most out of control dogs will learn to respect their owners when the owners step up and control EVERY SINGLE aspect of the dog's life.
That kind of structure, along with a strong alpha attitude should help a lot.
If you're not strong enough to correct/immobilize the puppy for biting you (or if she's really too wild), maybe you can introduce her to a prong collar. If it were me, I'd wait another couple of months before that... however if you just lack the physical strength to control her or are simply not a natural leader, a prong might be a good solution.
I'm not saying use the prong for obedience, for walks, for not paying attention etc. That's too much to expect from a 4-month-old puppy. But one good pop on the prong when she's wild and biting you WILL get her attention.
Just remember to always stay cool and not to get excited or annoyed when delivering a correction
Watch a program on how wolves interact with their young... that will give you a clear picture on how swift, strong and un-emotional a correction is supposed to be (and how effective it is when done correctly).
Good luck. Sounds like you have one fun puppy!
Are you trying to channel her energy and drives into training?
Working on building drive and focus should be great for your girl, might want to look into Ed's DVD on that!