My horse had a similar injury last January. I remember the vet had her some sort of injectable antibiotic for 5 days, then doxycycline twice a day for about 2-3 weeks.
My horse was an angel about all the treatments we did, so YMMV if yours isn't that easy to treat, but here's what we did:
-rinsing the wound with water for 5-10 minutes at a time, at least once a day, but preferably twice
-flushing it with that red stuff (betadine?). This was the worst part because we had to stick a catheter as far into the wound as we could to flush it from the inside
-stretching her leg to maintain flexibility while scar tissue formed. I don't think we started this until it was almost healed, but I'd recommend doing it now if you can. Stretch her leg as far up towards her stomach as she'll let you, hold it for a minute, then stretch it as far back and up as she'll let you. The reason I'd recommend doing it now is because we took her back to the vet for the third time because the wound was closed but she was still lame, when he lifted her leg towards her stomach a huge stream of puss literally shot out of her leg and squirted about 3-5 feet.
The outside had healed up, but there was still a lingering infection on the inside, which was why she was lame. The vet had to reopen the wound so it could heal properly. So don't worry too much about it looking bad on the outside right now. Like animalartcreations said, it needs to heal from the inside out.