Mri showed minimal nonspecific white matter change = diagnosis: migraines, premature vessel ischemic. doc said take topamax (topiramate) (24yrold-f). 2nd opinion?

Migraines: Migraines are associated with these types of white matter changes. The clinical significance continues to be unclear, but the minimal changes that you describe generally do not cause any neurological impairment. I would not necessarily describe the changes as "premature" because they do in fact occur in young patients with migraines.

Migraines: White matter lesions described may be seen with migraine, cigarette smoking, head trauma, hypertension, and aging. Would not worry about these lesions, and instead focus upon headache control measures, such as prevention with topirimate. But many other OTC and prescription items which can do as good or better a job without adverse effects from topirimate. Maybe HA specialist can serve your need