Herpes sore is another way of referencing the physical symptoms of a herpes outbreak. In truth it would be unusual for a herpes outbreak to produce a single sore: a herpes outbreak typically consists of a cluster of fluid-filled blisters that eventually scab over and heal. All told, a herpes outbreak that goes untreated will usually run two weeks or so. While herpes outbreaks don't require treatment and will clear on their own, they clear much more quickly when effective treatment is used. When a herpes sore or a herpes outbreak is apparent, herpes is at its most contagious.