After primary infection with Herpes type 1, the virus, remains latent (dormant) somewhere in our nervous system and in some people, it tends to cause recurrent infections.
The recurrent infection is also referred to as a non-primary infection. What usually happens is the development of a localized lesion, sometimes it can be big and other times smaller, and it is usually in the lip area, as you can see in the picture.
Is there a cure? Read all of primary and recurrent cold sore in the next link.