My Dog Had All Of Her Remaining Teeth Extracted Due

My dog had all of her remaining teeth extracted due to infection. Ever since she has pawed at her mouth, shaking her head, At first, I thought she was having a seizure, Took her to the vet who prescribed gabapentin 50 mg, She has been on it for about 2-3 weeks and still does the peculiar antics, What to do? And why is she doing this.