The main causes of acne are the following four factors: excessive keratin precipitation in pores, excessive secretion of sebaceous glands, inflammation and proliferation of acne bacteria. At different stages of the human body, most acne occurs because of the interaction of these four factors. ? There are mainly the following types of acne: adolescent acne: mainly because of the increase of puberty sex hormones, resulting in excessive sebum secretion in sebaceous glands, causing acne. Adult acne: It is also due to hormone secretion, but unlike acne, it mainly occurs on cheeks, around lips and chin. It is characterized by very long onset time and high recurrence rate after treatment. Blackhead/Whitehead Acne: Because the epidermis of the skin is too thick, there are too many cuticles and the pores are blocked, the sebum after secretion cannot be discharged to the outside of the skin. These sebum will accumulate in the skin and form white or black acne. Inflammatory acne: If sebum cannot be excreted from the skin, it may further cause inflammation, accompanied by pustules. This kind of acne will leave traces such as red acne marks or acne pits after treatment.