On 25mg topamax (topiramate) (for headache) 2x day, been on it less than a week.headaches have increased greatly, is this a side effect? do i need to see a dr?

Call your Dr: A change in the pattern of your h/a, particularly for the worse, and when starting a new med means you need to call your dr. It "might" be an effect in you (from the med), or might prompt more rapid dose adjustment, or a change in med(s). Let your prescriber know asap.

It may be so: It may be a coincidence but topamax (topiramate) can rarely cause headaches too you should discuss with your doctor or neurologist about it.