Laser PK Birthmarks] Birthmarks are clinically divided into red birthmarks and black birthmarks. For black birthmarks, laser treatment is better, nevus of Ota or zygomatic melanoma such as dark brown or brownish-black birthmark effect is good, usually need 4-6 times of treatment will reach the role of obvious fading. Black birthmarks like coffee spots, coffee-colored, lighter color in black, the treatment effect will be poor, but also can reach 60%-70% effective rate, so this part of the patient to seek treatment is also more. For the treatment of red birthmarks, such as bright red nevus, strawberry hemangioma, cavernous hemangioma, etc., because of the different principles, the laser is mainly targeted at the bright red nevus category. The laser used for bright red nevus is dye laser, and the cure rate for bright red nevus can reach 20%-40%. At present, with the birth of new photosensitizer drugs, photodynamic treatment for nevus erythematosus has greatly improved the efficiency. So different birthmarks using different lasers, the efficiency is also different, for patients with birthmarks, it is recommended to go to the hospital to let the doctor to give a correct diagnosis before giving the treatment of laser treatment and recommendations. PK Laser for Acne Marks] Acne marks are usually divided into several categories, such as red acne marks, brown and black acne marks, and acne pits. Lasers work well for different colors of acne marks. For different acne marks, different lasers are chosen. For black acne marks, you can choose the photoelectric type, you can choose the intense pulsed light, i.e. photon, like the Q laser or picosecond laser, or even the ultra picosecond laser, for the black acne marks have the effect of promoting the fading, and the onset of the effect usually takes 1 week to 1 month. Laser treatment of acne marks is merely to accelerate the process of acne mark fading, and clinically there are often patients who want their acne marks to completely fade away in 1 week after a laser treatment. From a medical point of view, this process is against common sense. After one treatment, the acne mark will significantly diminish, and multiple treatments are used to accelerate the metabolism of the pigment and even the absorption of the red acne mark. What doctors can help with is accelerating the fading of acne marks, not immediate results after treatment like an eraser. For acne pits treatment, carbon dioxide laser is used, the treatment is effective, but the result is also very good, just need multiple treatments, usually 3 times can improve 50%-70%.