Some people may not know that makeup cosmetics also have an expiration date, and some expired lip gloss still looks good, so some people still can't help but continue to use it. However, this is not advisable because some chemicals are added to the lip gloss during the production process, and after the expiration date, these chemical ingredients deteriorate and may form harmful substances, which may cause allergies and redness and ulceration of the lips if they continue to be used. Moreover, after opening, the lip gloss can easily become a breeding ground for bacteria. The use of expired lip gloss can cause dermatitis, acne, clogged hair follicles, eye infections and lip ulcers, and can also cause skin lesions that can cause cancer. Therefore, it is recommended that you try to avoid using expired lip gloss.