Hah! Obviously this girl has never had a puppy before. They bite. They bite anything and everything. They will chew anything and everything. Chair legs, your legs, door/window frames, and carpets can be endless fun for them (they'll leave a looooong visible trail where they pulled up until they ran out or got caught ๐คฃ).
Her reaction was great though! If a puppy bites you it won't really hurt that much (more of a gentle pinch than an "Ouch! Fuck!") but you have to sell it! When a puppy bites you, react loudly like they just sucker punched you hard in the face while insulting your mother. Act! And don't interact with them for a minute or two. If you're holding them, put them down and be like, "I don't play with dogs that do that! ๐ค"
That's how they learn that biting is bad. Also, always have treats handy for when they do good things and teach them to have a gentle mouth the same way as teaching them not to bite. Keep a death grip on the treats when you're teaching them this because if they were too rough but got away with the treat they won't learn.
BTW: Puppies have sharp teeth. Way sharper than an adult dog. You're much more likely to get scratches from their biting than bruises.