The stupamax dumbness does go away. I used to pride myself on my vocabulary skills and being very articulate. Then I started Topamax and I felt as if I had lost the ability to speak coherently. It was awful. It still happens occasionally but not nearly as bad. I take my first dose at noon and my second dose at bedtime, and that seemed to have helped, rather than the usual early morning and nighttime dose.
Also, brain games and memory building tricks helped as well.
The reason I stuck it out was because it's the only med that's helped with my migraines. To me, that was worth it. You have to ask yourself that question. Give it time, see if the side effect subsides, do some maneuvering of the med-time if you need to, and go from there.