Acne is medically known as acne, and old hard acne may be caused by not paying attention to skin cleansing, improper diet, endocrine disorders and other reasons. 1. Not paying attention to skin cleansing: If people with strong sebaceous gland secretion don’t pay attention to timely cleansing, the mouth of the follicle glands will be blocked, resulting in the accumulation of sebum that can’t be discharged, and then acne will be formed easily. 2. Improper diet: Eating a diet that is too oily, high in sugar, and spicy and irritating foods will easily increase sebum secretion, and if not cleaned up in time, it will easily cause acne. 3. Endocrine disorders: irregular work and rest, often stay up late will lead to endocrine dysfunction, the body’s hormone imbalance leads to sebaceous secretion disorders, the skin is easy to get oily, good acne. If you have hard acne that affects your normal life, you can go to a dermatologist for a checkup to find out the cause of the problem and treat it accordingly, and you need to develop good dietary habits and a good routine to avoid staying up late.