Dior makeup artists' secret weapon: a radiance-boosting brush that corrects dark areas, sculpts and illuminates facial contours like a pro. How to apply dior skinflash: Before or after foundation, apply Skinflash as a touch of light to 5 key areas of the face to brighten, cool down or sculpt: tip of the chin, line of the nose, forehead, cheeks and nose contour. To maximize the light effect, choose a shade of Skinflash lighter than your usual foundation.