I think I'd watch her for a little bit. If she continues to shake, I'd give her a little nutrical. If that doesn't help and she doesn't potty soon, I'd take her in. Lucy hurt her back right leg one time and held it up for a week even after a vet visit and x-rays showed nothing.
My vet told me once to give 1/2 of a baby aspirin for pain to see if it helped, but then told me if it didn't to bring her in.
__________________ Kim , Rebel ,and baby Dixie 
RIP my sweet Lucy |