How can I get rid of scar tissue in my lip? (photos)

As a child I had a very bad habit of sucking my bottom lip. I continued the habit for about 13 years. As a result I have permanent swelling on one side of my bottom lip. The swelling has caused a very asymmetrical appearance, especially during speech. I was wondering if there were any procedures that would give me a more symmetrical look. If so, what would this procedure be called and what would be the estimated price? Very desperate!