you could try and clean the area - make a weak saline solution by dissolving some salt in boiled water, and use a soft cloth (towel or a flannel) dipped in the solution to soak the scabs off. if there's any inflammation, it should help with that too.
i know this may not be the easiest of things to do given it's a new chin and all but it will give you an idea of what you're dealing with.
is he eating? drinking? moving around? looks bright? pooing ok?
in any case, i would take him to the vet. if it's a bite mark or an injury, it can get inflamed and he may need antibiotics. i don't have any experience with a broken tail but that would need a vet too.
if you can get to a vet, great. if not, given the time of year, i'd try to clean it, see what it is, give a vet a ring, explain and they will decide if it's an emergency or not. my vet, during out of hours, if they decide the case is not an emergency but there's something you can do at home, they'll give you advice over the phone. maybe yours does that too!
i'm wondering if you could call the pet store as well and see if they know anything about it.