Hey guys, Roxy my GSD has been acting really bad lately, she has been biting at my hands and face A LOT, today she re pierced my left ear lobe for me and almost ripped it open. I am trying to redirect but she just bites at my hands while i am doing it. She might have been playing but she has begun to snarl and growl during play, or when she does not get her way. Is it time to begin negative re enforcement? I mean she is only 13 weeks but damn she is so uncooperative. Is this just a phase or what?