a VERY easy to do VERY convincing scar!

Step 2 What you will need…

Most importantly you are going to need
Some free time (it took me about 30-45 minutes to do this WITH taking the photos with one hand and WITH typing all the below. I recall making these in less than 5 minutes)
glue,
a sharp scissors
and thread.

The basic ingredience could come down to only the above But to have the glue stick longer and better;
Ethyl alchohol would help.
Aditionally you may want to have some
painting material to your choice.
and a set of brushes for afterwards...

To remove the scar:
Aceton works best (NOT on the picture... sorry hadn't crossed my mind until I was finished with the instructable).

Aids;
Some of you may want to have a set of
tweezers
or helper hands as well.

You can pretty well manage without the aditional materials stated... it still looks amazing.

Edit: Super glue is a 'healthy' choice it seems... thanks for the heads up Kiteman!
Only thing I could say through experience is that it is less flexible and can layer easily from reapplying. But did have a natural 'crust' feel.