Herpes lesions are the typical symptoms of a herpes simplex virus infection. Herpes lesions are also referred to as blisters, and in the case of oral herpes, cold sores or fever blisters. Not all herpes simplex virus infections present symptoms. When an outbreak of lesions is present, herpes simplex is at its most contagious. An outbreak of lesions is the typical symptom for both oral herpes infections and genital herpes infections, though oral herpes and genital herpes are usually caused by different strains of the herpes simplex virus. Left untreated, an outbreak of herpes symptoms will typically run two weeks. With treatment, an outbreak of herpes symptoms can clear within days.