Covering up scars can require a little extra makeup know-how. Few of us are blessed with perfect skin. The cosmetics of evening out, brightening and hiding a blemish or two are some of the most basic in the makeup bag, and most of us know them well: cover-up, foundation, perhaps a color-correcting palette. These tools are typically enough to downplay small inconsistencies. For larger challenges, though, like significant scars or birthmarks, more skill can be required. Here, some tips to help the...