What should I do about dull, yellowish skin from staying up late every night?

It is recommended to adjust your daily routine, avoid staying up late, and ensure adequate sleep. Increase intake of vitamins C and E to promote skin metabolism and antioxidant activity. Use skincare products containing ingredients such as vitamin C and arbutin, which can help brighten the complexion. If dullness and sallowness persist, consult a doctor to rule out underlying medical conditions. Adjusting lifestyle habits and improving both internal health and external care are key to addressing dull and yellowish skin.