After the first infection the virus gets into the nervous system where it stays latently without transforming into real herpes.
Oral herpes can appear for various reasons, especially:
Afterwards the virus hides in the nervous system again and waits there for another trigger – and the opportunity to form visible herpes once more.
This is a very efficient strategy which has enabled the virus to survive for centuries. In the first stage when the lip just tingles, itches and tickles softly, the skin cells used by the virus as factories must increase their metabolic activity - meaning they do so “on demand” for the virus.
Then they start to build, multiply and replicate in accordance with the genetic information of the virus – simply put, they start creating its copies. Many copies.
Once the cell is not able to cope anymore, and is filled with many “descendants” of the initial virus, it ends its life by bursting. This is the moment when, together with the contents of the blister, a large number of viruses (virions) are released into the surroundings. In case they find a new organism, the whole cycle repeats and it is spread to another person. Unfortunately, even after the scab is healed, the virus hides in the nerve ganglia and waits for the next good moment to form visible herpes.