Eligible subjects will be randomized 1:1 in a blinded fashion to receive onabotulinumtoxinA at 31 fixed-site, fixed-dose injections across seven (7) specific head/neck muscle areas and daily topiramate (Group A) or onabotulinumtoxinA at 31 fixed-site, fixed-dose injections across seven (7) specific head/neck muscle areas and placebo to match topiramate (Group B).