If it is just a surface wound you more than likely will not need antibiotics (unless there are signs of infection of course). One of my rabbits was hurt while was was on vacation and when I came back she had maggots all over her. They actually opened up the wound so much that I could see into her abdominal cavity through her hind leg!! I cleaned it out and kept her in the house until the next day, then I took her to the vet. Maggots are a really good thing but I was planning on taking her to the vet and I didn't want them dropping out ever where. Peroxide can dry out the area. I'd try the bleach water solution someone suggested. If it gets bad enough give it penicillin. The vet we took her to is the cheapest well know clinic in Indiana, they only charged me $15 to clean the wound, administer a penicillin shot, oral antibiotics for home, and a cleaning solution for it. For that open wound it took 3 weeks to heal. Open wounds like hers has to heal from the inside out so that it doesn't abscess.
Good luck and I hope this info helped, if not now then future references.
Goo nutrition is key to a quick recovery. Make sure he's eating and drinking really good.