Board Thread:Speculation House/@comment-12748424-20130719231055/@comment-11188061-20130721143308

The makeup was specifically used to hide the scar. As you already know dear Weiss is quite the important person, so perhaps to her guardians or herself the scar is a sign of weakness. A little white-colored padding would be enough to hide it since the scar's shallow enough not to hurt her eye.

During her concert she either did not have time to redo it (which if it's true would be a huge ass lame waste of a good setup), or she had come to a resolution with herself and no longer fear or treat the scar as a sign of weakness.