Concealers are any makeup savvy girls beat friend. They do everything under the sun, from correcting your complection to eyeshadow base. For the girls that do not like to wear foundation, concealer is a spot treatment for the few areas you may have to fix. If you do like to wear foundation, concealer can be put on before or after. When putting concealer on before foundation, make sure they are the same color and wait awhile for the concealer to settle into the skin. When putting it on after you can see the areas that the foundation did not completely cover, so it is easier to correct those smaller areas. For under eye concealer it can be the same color as the foundation or it can be shades lighter than the foundation to brighten the face. Any makeup brush company makes concealer brush for a more even coverage. The famous celeb that loves lighter under eye concealer is Kim Kardashian. When you do put concealer anywhere make sure you set it with a powder so it will be more long lasting.