How long it takes for a black mark left by squeezing a pimple to heal itself generally depends on the degree of skin damage and how well the skin repairs itself. After squeezing a pimple with your hands, you may usually leave a black pimple mark. And acne marks can be divided into two kinds: one is the pigmentation left after only damage to the superficial layer of the skin, with the extension of time, acne marks will gradually fade on their own in about 3-6 months. The other kind is the atrophic scar formed after the injury to the dermis of the skin. Once the scar is formed, it will not heal itself even with time and will not fade away completely, but it may slowly lighten after about 1 year. In the case of dark marks caused by hyperpigmentation, it is important to avoid light and actively practice sun protection in daily life. If the dark marks are caused by atrophic scarring, fractional laser and microneedling can be used to help remove the skin scarring.