In _The Elder Scrolls V: Skyrim_, vampirism is a disease that can be contracted by being attacked by a vampire. Vampires have a number of special abilities, including the ability to turn invisible, see in the dark, and regenerate health rapidly. However, they also have a number of weaknesses, including a vulnerability to sunlight, fire, and garlic. If you contract vampirism, you will need to find a cure in order to return to your normal state.
There are a few different ways to cure vampirism in _Skyrim_. One way is to find a vampire cure potion. These potions can be found in a number of places, including the College of Winterhold, the Temple of Mara, and the Blue Palace. Another way to cure vampirism is to complete the Dawnguard questline. This questline will lead you to a cure for vampirism, but it is a long and difficult quest.