Leather tips from a costumer

[M. Demetrius]

It may be that it's not so much that the edge/border is raised, but the center is depressed. There's a leather tool called a beveler, which presses down at an angle, and makes what's next to it be higher.

Notice how the leather in the center is darker? That often happens when it's compressed by a tool.

http://tandyleathercompany.com/products.asp?dept=406 gives a sampling bevelers. Obviously, for a longer line, you just follow a cut or scribed line down the edge of the leather, and overlap the impressions.