even the humane society, aspca, or spca have vets there that can treat the kitten.
the vet likely will not charge you if its not your kitten. please take this baby to the vet asap.
i once took in an injured baby bunny that my cat had gotten ahold of. it had a broken leg and i rushed it to our vet. they had to put the baby down, but i didn't have to pay anything.
OH please take this kitten into a VEt......explain it isn't your kitten and they will see to it getting some help....a clinic or a a shelter, you CANNOT TREAT this on your own, where did you get the antib?
Please take it in for help this kitten is suffering......bless you both, keep us updated PLEASE..♥