I took my cat, Thor to the vet yesterday. He got an examination and a distemper shot. When I brought him home, his brother Loki started acting really mean towards him. He was hissing and trying to swat at him. I take my cats rutinely to the vets and this sort of thing has never happened before. Loki usually goes the most because he has had lots of food allergy issues, and he hates the vet. I tried separating them (the whole night), I tried feeding them together, and playing together. But as soon as Loki smells Thor he starts acting up (I also tried rubbing him down with some dry shampoo to take some of the smell away). I'm not sure what to do at this point and I'm really worried, any advice would be much appreciated.