Cold sores and blisters
As Herpes Simplex Virus Type 1 (HSV-1) is passed from person to person by direct contact with infected skin or secretion, it causes cold sores and fever blisters. Cold sores are often found in clusters on lips. Most people are affected by their adulthood; a blood test can help you identify HSV-1. Cold sores or fever blisters can be diagnosed by your dentist with various methods.