What type of seizure disorder has she been diagnosed with? Are the headaches part of the seizure disorder?
There are many newer medications that could be tried in place of the Dilantin -- Depakote, Neurontin, Keppra, Topamax, Zonegran, Lamictal, Lyrica, and more. These are also used for headache and Migraine prevention, but she nees to find out if the headaches are part of the seizure disorder, or if they're not, what they are. If her current neurologist can't diagnose the headaches, a headache specialist would be a good step. She can check our listing of patient recommended specialists for help locating one.
"Living on Tylenol" can actually make things worse. Taking it more than two or three days a week can cause medication overuse headaches, aka rebound. You can find more information on that in Medication Overuse Headaches - When the Remedy Backfires.
Good luck to you and your daughter,
Teri