A Answers (1)
Stacy Wiegman, PharmD, Pharmacy, answeredIf you have a cold sore, it will be highly contagious the entire time it is visible. It will be most contagious when fluid begins to leak from the blister or blisters that have formed. This fluid contains the infectious virus that causes cold sores. When you have a cold sore, don't share anything that touches your lips, such as cutlery, dishware, or towels. And if you happen to touch the cold sore, wash your hands right away.