Oh my! These can be painful, but you should be okay waiting till morning to head out to your vet. Antibiotics are usually prescribed, and surgery maybe to place a drain to get it to heal properly. It all depends on how bad it is, his age, bloodwork, and any other things the vet factors in. As it's already open and draining, butt soaks and ABs may do the trick. Keeping him in my prayers.... and you too!
