According to Sr. Dermatologists, Your skin is your biggest organ, and it must be tended to. As its constantly working 24 hours a day. During the day, your skin is in protection mode , keeping your complexion free from harmful rays and free radicals. At night, your skin goes into repair mode creating healthy cells, regenerating levels of collagen, and more. By sleeping in your makeup, your skin has to work way harder to get through all that makeup and dirt.
Read what effects does sleeping in your make-up to your skin: