My cat is an older cat and he was in the garage then next thing we know he is like crying we let him in and he is limping but there is no open wound on his arm. Its swelled triple size in about three hours and can't walk now and its hot to the touch what could it be and what should we do. Its to late to take him to the vet and money is tight so I don't know what to. It could be some kind of bite but can't find any open marks or bleeding.