This is what's known as a Muslim prayer bump. It's what happens when extremely devout Muslims pray too much. It forms a horrible mark on the forehead.
Whenever you see this mark, be prepared to get a strong dose of radical Islamic rhetoric.
Usually when people pray allot they become more peaceful, but not Islam.
Keep this in mind next time you see someone on the news with this marking. They're easy to spot now. - N.P.Contompasis