There are many reasons why concealers can separate under the eyes. You may have dry, oily, or flawed concealer formula on your face. When concealer is kept past its expiration date, it might break up and perform poorly on the skin. Concealer patching can be prevented in several ways. Make sure you have the right tools. A damp makeup sponge is a good option because it easily blends out the concealer without leaving a lot of product sitting on the skin. Mattifying products can be applied in thin layers, slowly building up coverage as needed. Use a tissue to remove the excess concealer that may have gotten into your creases after applying your concealer. Once you remove the excess, apply a thin layer of translucent powder to lock it in place.