Concealer can be used to cover up and disguise all manner of blemishes from dark circles to spots. To lighten dark under-eye shadows, you can either use a paler shade of foundation than you have used on the rest of your face, or a purpose-made concealer. These provide more coverage than foundation since they contain more pigment, but it is important to find one that is not too heavy in texture so that it doesn’t settle into the fine lines under your eyes. A light-reflecting concealer is especially good, and can also be used around the sides of the nose and where lines develop that run between the nose and mouth.
Concealer is also useful for hiding the fine, purple veins on the eyelids, at the same time providing a base that will hold your eye make-up in place for longer. However, they should be applied very sparingly. Choose a very liquid concealer, perhaps one that is delivered via a pump-action brush or one that comes with a sponge applicator. Otherwise, using a small, firm eyeshadow or lip brush to apply concealer will give the best result. You should also check that your concealer is only slightly lighter than your foundation to avoid the panda-eye effect.
A heavier formula is appropriate for concealing spots. Look for one that is designed for the purpose as it will be oil-free and will contain healing and antibacterial ingredients.
Photo not mine