I am looking for a movie about a goodlooking mean kid whose outside appearance starts
To change to show all the ugliness that's been inside of him. His outward appearance becomes ugly. This happens I believe to teach him about kindness etc.

The original story that this sounds like is one by Oscar Wilde called "The Picture of Dorian Gray."
I am not sure if you are referring to a remake with slight change of storyline known by a different name. There have been a number of movies based upon that story. Here are a couple for you to look at:

Dorian Gray (2009)

http://www.imdb.com/title/tt0364599/

http://www.imdb.com/title/tt0258534/

The Picture of Dorian Gray (1945)

This lists many, if not all, the adaptations of the story:

Adaptations of The Picture of Dorian Gray - Wikipedia, the free encyclopedia