Acne marks are also known as acne pigmentation, which may be red or black. 1, choose photon: the mechanism of action of photons to remove acne marks is selective photothermal action, after a certain wavelength of photons act on the pigment cells, the pigment cells absorb energy and slowly make the melanocytes in the body smaller and more fragmented, and the macrophages in the body slowly take it away after phagocytosis to play the role of lightening pigment, which of course takes 2, the choice of fractional carbon dioxide laser: the choice of energy, density is very important, you can choose low-energy, low-density treatment. 3, with the pigmentation products: such as topical niacinamide, mucopolysaccharide or hydroquinone, these have the effect of lightening pigmentation, you can also use salicylic acid or fruit acid, etc., also has a certain effect of lightening pigmentation, also need some time.