Here we have a 3-yr-old kid allowed to play in the backyard alone. He sticks his head in a hole in the fence, calls over the neighbor's dog and is bitten for his trouble.
How many times was he bitten?
How hard was it to remove the dog from the child?
Didn't have to - the dog bit once and backed off.
A dog bite from a medium-large sized dog to a 3-yr-old's lip is obviously going to tear some tissue. The boy lost part of his lip and has some damage to his tongue.
But this is not a mauling, people. This is a dog reacting appropriately to a noxious, potentially dangerous stimuli - a screaming child invading the dog's territory. This is not an excuse for the dog's owner, who should have remedied the open hole.