The "ouch" only works if you pair it with removing your attention from her. Actually turn your back to her and don't give her attention no matter what she does. If this doesn't work, e.g., she still solicits your attention, leave her sight (go to another room, go into the house and leave her alone in the yard, etc).
Use a clicker or positive reinforcement to reward her when she's being calm. She would be classified as reactive by some behavioralists, meaning, she reacts to stimuli in an undesirable manner. (Note: this does not mean she's a bad dog). Help her learn that calm behavior will be rewarded. Read, "Click it Calm" by Emma Parsons for more extensive exercises if you need more ideas than what's been posted here.
I agree with all the folks who say "ow" or "ouch" and stop playing. This also works with rabbits.
Dont use your hands as a play toy. Only play with toys. They'll associate hands with toys forever and then always wanna bite. And yes, when they do bite the hand, always scream by saying a key word. Always use one word so it's consistent. But definitely stop using your hands as toys. Play only with toys.