I'm on the topamax, had bad acne as well in HS...no acne with the topamax. And a good side effect with the topamax is that I have lost weight. But no acne side effects with the topamax. been on it for a few yrs now.
I do have very sensitive skin. I get a bit of acne occassionally, but didn't have a big problem on Dilantin or Keppra. I recently switched over from Keppra to Lamictal. Lamictal is supposed to have rashes as a side effect. Ironically, my skin has never been smoother. Even the melasma I had on my forehead has disappeared. I didn't think I had a problem before taking it, but definitely notice my skin looks nicer now.
Good luck. There has to be something else you can try.
My sister takes trileptal and does have acne, but that is because she's also allergic to dairy and wheat. Her acne is related to allergies, not her medication.