My Sheltie angel, Pixie, had seizures for most of her life brought on by vaccines recommended by my then vet when she was a puppy. Bravecto is known to have side effects which include seizures. I'd be very careful giving your girl any flea and tick meds now, even though that's not why you were prescribed the Bravecto. If you are using one I'd stick with the most mild spot-on you can find, or a natural remedy.
We were fortunate with Pixie. I took her to another vet (who I'm still with 20 years later) who recommended holistic treatments for the seizures and a careful diet. In a few years on this protocol, the seizures diminished. Hers were also after exercise, fairly mild and short in duration. I just held her while they were happening and then gave her a spoon or two of vanilla ice cream afterward, which was recommended. She was always just tired and sleepy when they passed.
I hope your pup recovers and the seizures stop. How old is she?