In The Mark of Athena, we see the villain Chrysaor, also referred to as the Golden Boy. He wore a gorgon mask that covered his face. When Frank Zhang attacked him (in the form of a grizzly bear), he swiped off his mask. Chrysaor screamed, covered his face, and dove into the sea.
Why? Why would he cover his face? What was under the mask? Answers from Rick Riordan's books and/or Greek mythology are welcome (so anything from the old stories works, too).