There's an OTC lip stuff called "Herpecin L" (I know, terrible name!) but if you
can zap it when you first feel it it won't develop into a full blown thing. I think
the directions say apply liberally once per hour. I think if you're vigilant, you
can avoid getting them. (It's been years for me)

Eat foods high in l-lysine or take supplements. Fish/shellfish has a lot. Avoid
chocolate and nuts. I still eat fudge this time of year, but take an extra tab of lysine
with it. And I'm religious about applying SPF 30, won't even got out to the
mailbox without it.

Get plenty of sleep. Try not to worry about them, the stress of that can actually
bring one on. I know it's hard to do, believe me.