What should be done about dull, yellowish skin in teenagers?

For teenagers with dull and sallow skin, it is recommended to maintain a balanced diet rich in vitamin C and antioxidant foods. Perform daily sun protection to reduce UV damage to the skin. Ensure adequate sleep to promote skin metabolism. Additionally, consider using skincare products containing ingredients such as vitamin C and arbutin, which may help brighten the complexion. If there is no improvement after a prolonged period, seek medical advice to rule out underlying health conditions.