Read this last night and I thought it was really good so I'm going to post the link here. Despite the user-pic this is a BBC Sherlock fanfic, I haven't updated my userpics yet. This is on Fan Fic Net - but don't just dismiss it -- it's a good story that deals with a topic that's come up in a lot of Sherlock fics in a new and different way. BTW - this is slash but not overly graphic.
Of scars and other demons, a Sherlock fanfic - FanFiction.Net