I am sorry your Mishka is hurting. As to that toddler...I say if it has feathers, quacks and looks like a duck, it's a duck. Something happened to him! I am sure it was not intentional, but I would make sure it didn't happen again. Lay the law down...tell them if they are ever there again, to please crate Mishka or put him in another room. Children and small pups do not mix! I have cared for countless yorkies over the years that were hurt by children..not intentional, but hurt nonetheless.
Praying he is fine with meds and rest.
Nice to see you btw.