OMG OMG OMG OMG OMG OMG! I would have freaked out and (knowing my extreme temper) slapped the hell out of that girl!!
Your poor little baby! A piece of her tongue is missing now?? OMG I can't even imagine how painful that must have been for her. I would have ABSOLUTELY contacted a lawyer and there would be no way in hell that I would have paid and tipped that girl. They better give you a full refund and pay for any and all medical expenses that you incur.
Codie and Katie send gentle kisses to your little one. I hope she feels better soon!