Cold sores, also known as fever blisters, can appear on your mouth or lip and are usually caused by oral herpes or herpes simplex virus type 1 (HSV-1). “It’s extremely ubiquitous,” says Alexandra ...

Cold sores are caused by the herpes simplex virus and can be both painful and disruptive. While a poor diet can weaken the immune system and increase susceptibility, certain healthy foods may also ...