If you look at the picture of the "bite," it doesn't look ANYTHING like a dog bite.
I have been bitten by a dog before, and it certainly didn't look like that. I also own 5 dogs, and can tell the difference between a playful nip and a "shit that dog is going to eat me" bite. I understand that a child would likely not be able to tell the difference, though.
It also sounds like the adult that took the kid to the freaking ER overreacted quite a bit. If it were me, I would look, see no bleeding, maybe grab an ice pack for any swelling, and call it a day. Taking the kid to the ER because of this was ridiculous.
And don't worry about the post in the general forum. Too many M3 owners get their panties in a bunch when a mistake is made and will bash you instead of reporting the thread to be moved.
I reported it so a mod can delete it or redirect it here.
'11 BMW E92 ///M3 - ZCP and DCT
'15 Ford F-250 - Lariat, 6.7 Powerstroke Turbo-diesel