bruising after neuter

My 6 month old kitten, Oliver, was neutered last Tuesday, and he also received his rabies shot that day. Ever since then, his appetite has just been off - he will scream for food and then only eat a few bites before ignoring it. He will, however, eat treats and take cooked food (like chicken)...

I had Poet neutered this week and he developed horrible bruising. It's gotten worse since Tues morning when he was neutered. I took him back to the vet and he wants to wait a couple more days to see if it clears up. Anyone else experienced this?