As its the day after the fight I'd suggest home care and seeing your vet on Monday.
You can read about the antibiotic here
http://www.petplace.com/drug-library/cephalexin-keflex/page1.aspx
scrolling down for all info on cautions and dose etc.
For topical care of the bitten spot you can use a warm/hot damp compress on the area to help it stay open and drain of infection. This will also stimulate blood circulation to the area to help fight infection. Make sure to trim the fur back away from the wound area to help keep bacteria out of the bite. You can clean the cuts out with Betadine iodine solution, chlorhexiderm solution, sterile saline, or 3% hydrogen peroxide. Then apply Neosporin or Triple Antibiotic ointment to the wound or any scabbed over areas. Keep the dog from licking the ointment off. It won't hurt the dog if it gets licked but it does better on the wound than on the tongue. A bit of peanut butter on the roof of the mouth can keep the tongue busy while ointment soaks in.I'd do this 2-4 times a day.
Also check for another injury now its been a bit. Feel through the coat for scabbed over areas and look for a reciprocal bite wound. Often what is really visible is the bite injury from top or bottom teeth and there is another puncture where the other side of the mouth was on your dog's body.
Hope this helps you!
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics