Concealer is used to minimize the appearance of dark circles, blemishes, and imperfections, and the specific formula determines whether to apply before or after foundation. For example, we recommend applying our Instant Full Cover Concealer works before foundation, while our Skin Concealer Stick should be used after foundation. It is best to read the directions for the specific concealer you are using. You can also talk to one of our experts today about applying foundations and concealers.