Your dog needs to be seen by a vet. An open, non healing wound needs professional care and treatment.
A dog who has had a seizure also needs some care, but if its been many months since she had one, that might not be an issue right now.
Hi there...peekawho is correct, this wound needs veterinary attention.
Often, a little scratch, insect bite, or other type of seemingly insignificant wound can drive our dogs crazy!! Its almost as if the dog becomes obsessive over the wound and, as you mentioned, will not leave it alone. This constant licking and chewing prevents the wound from healing naturally and can cause a bigger problem down the road known as a lick granuloma.
The key to healing these stubborn wounds is to get the dog's mind off of the wound. Some veterinarians will inject steroids into the area to minimize the inflammation and the symptoms, others might recommend a surgical approach to remove the wound. As you make your appointment to see your veterinarian, you might consider putting an elizabethan collar on her (the "cone") so that she can't reach the wound to lick it. You can buy one at local petstores.
Good luck...I hope you will check back and let us know how she is doing.