How Can A Cold Sore On The Lower Lips Be Treated?

I have a cold sore on my lower lips. It only attack me during my menstrual. What can i do to avoid the recurrent. I have been suffer the recurrent for the past 2 years. My cold sore is not due to food allergy or sunlight. All vitamin or antiviral didn't help. I know there is no vaccine at the moment but at least let me know how can i stop it from outbreak so often. My menstrual been very puntual. So I have to suffer the outbreak every cycle.