The Cure: If your dark circles lighten when you press on them, they're likely caused by blood vessels showing through your skin. The thicker your skin, the less visible the vessels will be. Apply a retinoid cream underneath your eyes every night to build collagen and plump your skin. (Ask your dermatologist for a prescription or try an over-the-counter version like RoC Retinol Correxion Eye Cream, $22; drugstores.) Top the retinoid with a rich eye cream that will reduce potential irritation and further fortify the skin. Allergies can cause the blood vessels underneath the eyes to dilate, worsening shadows; an over-the-counter antihistamine, like Claritin, will help.
The Quick Fix: These dark circles are usually blue-tinged so are best camouflaged with a creamy, yellow-based concealer (like Bobbi Brown Creamy Concealer, $23; BobbiBrownCosmetics.com). Lightly tap the concealer over the discolored areas.