I think Mr. Tyson hurt our Chihuahua Brian. they were playing and Brian fell off of the back of the chair, and by the sound that he made I thought that he was dying. He won't put his back rear leg down, and if you touch his paw he screams bloody murder. How do you know if it is broken, or just bruised? The vet said that it may be sprained but not to bring him in unless he doesn't start to try to walk on in for a couple days. But what if there is something really wrong with it. He is in pain . Anyone know, have helpful tips?