This could definitely be from a bite, or there could be another reason for the infection. It's best to get this seen by a veterinarian, because there could be something under the skin that will continually cause an infection is it's not removed. This doesn't appear to be an emergency, but it's best to have her seen in the next day or two.
For now, you can try the following:
1) Clip the hair around the area and expose all of the sore skin. 2) Wash/spray the area with just warm, clean water (no soap or other antiseptics) for at least 5 minutes at a time. Do this twice a day.