A cold sore is marked by a fluid filled blister that makes the skin red and swollen. The blisters of the cold sore are often very painful. When these blisters are filled with liquid, the first layer is very sensitive. Rubbing/touching it can lead to a nasty infection. If a cold sore treatment is applied in time, the chance of scarring decreases.
In most cases the blisters have the ability to recover. Unlike most viruses, the HSV-1 penetrates enters and never leave your body.