When you have acne scars or pigmentation, your skin tends to produce extra melanin, which can lead to dark spots and discolouration. Look for brightening products that target the spots from within, and help even out your skin tone with ingredients such as AHAs, Vitamin C, Retinol, etc. Always remember - using any of these actives will give you no results unless you follow it up with SPF to protect your skin from more damage and pigmentation.