CBS) LOS ANGELES It's a "mystery” straight out of the "X-Files." But those who suffer from it will tell you it's painfully real. Imagine sweating "beads” of a *black tar- like substance" -- or pulling colored threadlike strings from sores all over your body. Worst of all... not only are doctors unsure of what it is, many tell patients they're making it all up. The disease literally makes your skin feel like it's crawling-- but here's the real scary part for us. Out of the entire country, the L.A. area has the highest percentage of cases. According to some patients:...