Logan: Bless you for helping out at your local private shelter, and bless you for considering assisting them in starting a fostering program. And bless your vet for helping out the helpers! Butter's hair will grow back, it takes 3-6 weeks. Since he is a colorpoint, don't be surprised if it grows back darker, especially since it's winter. Some vets do clip for a neuter, just as a precaution, or if the cat has long or unruly fur.