Acne is mostly caused by two factors: one is that the skin is oily and the sebaceous glands are overly developed, producing too much sebum. If the pores are blocked or if there is poor oil drainage due to other reasons, then the sebaceous glands continue to secrete and sebum accumulates in the pores, protrudes and becomes acne. Another reason is that the body’s hormonal imbalance makes the skin acne. This cause is more common during puberty. Hormonal imbalance can also indirectly cause excessive sebum production, which further aggravates the acne condition. In the early stages of acne, endocrine secretion increases, stimulating the sebaceous glands and increasing sebum secretion, and because the sebaceous glands open in the follicular funnel, the follicles and ducts are stimulated to undergo a sterile inflammatory reaction. If the narrowing is not lifted, sebum excretion is further prevented. In the advanced stage, the epithelial cells of the follicular funnel are ruptured and neutrophils, lymphocytes, macrophages, and foreign body giant cells accumulate at the rupture site. In the enlarged follicle, there are inflammatory changes around the follicle and a significant lymphocytic infiltration is seen, while a small portion of the follicle wall begins to rupture. 1. Whitehead acne: This is due to the accumulation of keratinous material by the sebaceous glands at the mouth of the follicle – blockage, together with the expansion of the follicle mouth funnel, forming a white tip of small rice grains or some large raised papules, the rash has no inflammatory reaction and does not communicate with the outside world. 2, blackhead acne: the pathological structure of white acne, but with the outside world, so that the sebaceous gland follicle opening accumulation of keratin, sebum, stolen dirt and outside oxygen contact, resulting in the plug in the follicle sebaceous gland mouth of the cheese semi-solid, exposed in the follicle mouth of the outer end of the black, which is due to melanin. If squeezed with pressure, it can be seen that the head is black and the body is yellow-white translucent lipid plugs discharged. 3, papules: protrude skin surface, can have red, swollen, hot, painful small package, but also without red, swollen, hot, painful small package, with red, swollen, hot, painful is inflammatory papules, pathology can be seen around the hair follicle with significant lymphocyte infiltration, while a small part of the hair follicle wall begins to rupture. Those without redness, swelling, heat and pain are non-inflammatory papules, mostly due to poor drainage obstruction. 4, pustules: is the follicle wall rupture in the follicle formed after the purulent damage, containing more neutrophils and so on. Surrounded by many lymphocytes and polymorphonuclear leukocytes, sometimes staphylococcus can be found. If the damage has been prolonged, plasma cells, foreign body giant cells and proliferating fibroblasts may also be seen. Most acne is superficial in pustules with yellowish pus at the tip of a red papule that dries up on its own or dries up after breaking. A few occur as deep pustules, often larger than 1 cm in diameter, with tenderness, which may last from half a month to a month and a half. 5, nodules: This is substantial damage, nodules occur at the site of hair follicle rupture, is due to sebum, free fatty acids, bacteria and keratinized cells from the hair follicle from the rupture into the dermis caused by inflammation and nodules. Because the hair follicle is located in the deep dermis and subcutaneous tissue, nodules are also located in the deep dermis and subcutaneous tissue, dark red or purple-red, generally larger than 0.5-1 cm in diameter, its main difference with papules is deeper and larger than papules, sometimes only slightly above the skin surface, can last for several weeks without receding, sometimes necrosis, ulcers, usually forming scars. 6, cysts: is due to the follicle mouth blockage, the occurrence of nodules and other damage, coupled with surrounding inflammatory infiltration, so that the destruction of sebaceous glands, the retention of secretions, the expansion of the hair follicle caused by containing a large number of neutrophils, monocytes, plasma cells and foreign giant cells, keratin particles. Jelly-like or bloody secretions may be discharged from the pore openings on the cysts over time. In larger damage sebaceous glands are partially or completely destroyed sometimes becoming very large cysts. 7, scar: acne receding, healing, when acne, pimples, nodules, cysts of all pathological changes caused by dermal or deep tissue loss or destruction, the skin began to repair, but the body can only be repaired with new connective tissue, this tissue is no other function of fibrous tissue, more solid inelastic, after repair is both scar. 8.Pigmentation: The commonly referred to “red marks” are caused by the deepening or disorder of pigmentation after acne inflammation. Pigment deepening is the direct action of inflammatory mediators and inflammatory cells on pigment cells, making them accelerate their synthesis of melanin. However, some patients often squeeze their pimples intentionally or unintentionally, causing inflammatory reactions that eventually lead to pigment changes.