Granted, antibiotics can only be supplied by a vet, but for skin wounds, saline and rest can sometimes be enough. I wouldn`t fuss over him too much honestly. He`s been through a torrid time already and he`s probably either going to do well, or he`s not. I`m guessing that vets in the US don`t see many pet mice and if you did go, they would charge you a small fortune for Baytril or even just a routine check up. Mice are strong little creatures but if they are too ill to save anyway, you would know just by his behaviour and reactions.
Your doing fine by him, believe me. You also don`t need to pick the corn out of his mix. Wait and see if he wants to eat the corn. It won`t harm him. Always allow the mouse or hamster to decide what they don`t want or like.
Keep us updated and tell your dad that he shouldn`t worry about having the mouse. He may smell but he main thing is you to him out of a bad situation and anything that happens now can only be an improvement. x