How Long For Male Kitten Neutered To Heal?

i had a vet who told me one week, but i’m not sure if that’s true. how long is it going to take for him to be fine? he looked really bad when we left the vet from what they said and now my cat looks like he’s been shot half his body is black with bruises all over… please help

Kitten Neutering – Your Cat Will Be Fine | Petco Animal Hospital