Apparently Ronin did hurt himself, but it wasn't serious. He seems to be healing. He has some Ritalin (NSAID) to ease any pain.
So today we went to the park and had a good practice. We lowered the jumps a bit and he seemed fine doing all the exercises for Open B and Utility B classes. He got to meet a new puppy in the park as well as watch squirrels while practicing stays.
Yay, Ronin!