Cold Sores are caused by the Herpes Simplex virus.
They start off with a tingling, burning sensation usually around the lips. They typically take 10 days to heal and they are extremely contagious.
Tip - if you have one, don't kiss anyone as it is likely you will pass it onto them. Also don't engage in oral sex while suffering as you can give them genital herpes.
There are triggers for cold sores such as strong sunshine, other illnesses and periods.
The ideal time to treat cold sores is when you first get the tingling sensation, and then to use Aciclovir Cream five times a day for five days.
A Compeed Cold Sore Patch is a drug free alternative and also provides some protection from passing on.