Fractional laser usually treats 3-4 times before the results are noticeable. Fractional laser mainly refers to the carbon dioxide fractional laser, which is a physical treatment for acne pits or small scars. Through the stimulation of CO2 fractional laser, it can effectively stimulate the secondary proliferation of fibroblasts in the dermis and rearrange the collagen fibers to achieve the treatment effect. This method is more effective for depressed acne scars. However, the fractional laser has a limited depth of skin per exposure, and it usually takes 3-4 sessions to make the fibroblasts grow to the same level as normal skin. Since fractional laser is irritating to the skin, it is recommended that patients opt for cold packs after fractional laser exposure to help with overall recovery.