the skin around the wisdom tooth, when it is swollen is called pericoronitis. In this the skin around wisdom tooth gets swollen up due to some infection which can be due to food lodgement or trauma or poor oral hygiene. It is quite a painful condition and for this you can do warm saline rinses 3-4 times a day and take some pain killer. If it does not subside then you have to visit the dentist who after taking detailed history and clinical examinatin will do the treatment. If you want to know more about pericoronitis then you can check the following link in our website... http://www.identalhub.com/article_understanding-wisdom-teeth-152.aspx