A lip stain is a liquid product that is absorbed by the skin to give the lips a tint of long-lasting color. Unlike lipstick, which is a waxy substance that goes on top of the lips to color them in any hue you wish, lip stain is designed to be absorbed by the lips so that the color penetrates and lasts longer. Lip stains are lightweight, typically sheer in color, and relatively easy to wear and reapply throughout the day. Lip stains are not necessarily good or bad for your lips, but they can be a little bit drying because the formula is meant to dry down to a matte, natural finish. However, most of the lip stains on the market are filled with moisturizers like squalane and hyaluronic acid, which can help to counteract any dryness.