If this is the only place on her that has this problem, you can probably treat it topically to begin with. If you see other problem areas, or if this one keeps growing larger after starting treatment, you really need to take her into the vet so they can culture the area and see exactly what it is.

I would use hydrogen peroxide on the area twice a day along with Neosporin ointment. You can also purchase a product called Microtek Spray to use on the area. It is an antifungal, antibacterial/antifungal that will help with the spot in most cases. You can get this at most pet supply stores or online at www.revivalanimal.com.

The biggest problem you have with your girl is that she won't leave the area alone long enough for much healing to take place. I would get an Elizabethean collar from the pet supply or the link above and use it. This is a cone shaped collar that is used to prevent pets from fooling with problem areas like the ears of face. She probably won't like it, but it will keep her from digging the area. It will keep her off the spot and give the wound opportunity to heal. Again, if you are not seeing any improvement in a couple of days, please take her in and have the vet take a look.