I know how you're feeling. I've had epilepsy myself since 1979 and over the years, my Dilantin level has gone toxic a few times. If it goes like that for too long it can cause minor brain damage, for example, you could lose your short term memory or it could effect some of your motor skills such as your balance and your walking or even cause slurred speech.
If it is treated on time, the effects will eventually go away, maybe not right away but could take a few months but it WILL go away.
Diagnosed with epilepsy and ulcerative colitis in 1979,
Been on meds ever since.