Oh, yeah. Right behind the guy with a package.There actually was a large dog in the crowd, It's easy to miss but it is there.
But, I don't think she was attacked by a dog only, in chapter 6 he is interrogated by police and the detective said something about another dude who is in the hospital and not in a shape to talk(besides from Vi) and Valentine had bruised knuckles, so I don't think it's only a dog, perhaps some asshole dog owner was part of it too.
But Vi's scars don't look like from a dog bite. Chin, maybe but how can a dog bite you on the abdomen, almost perfectly straight, like a scar from appendicitis surgery?