If you're flying out of Terminal E (the International Terminal) then as I recall there really isn't much beyond the security checkpoint. There may be a news stand/bookshop and a cafe of some kind, but there aren't nearly the number of services as can be found in some of the other concourses. I think your best bet is to find sunblock that comes in a 3 oz. or smaller container that meets TSA standards. Don't forget the zip lock bag!