Microneedling is useful for treating depressed scars, but there are some risks involved. Microneedles are needle-like structures with different materials and shapes that can make the original depressed scars lighter by acting on the skin and creating different sized orifices that disrupt the dermal layer of the skin, and then collagen bundles in the superficial dermis stimulate the production of more collagen beneath the epidermis. Microneedling is a highly technology-dependent clinical treatment, and the number of microneedles, depth of microneedles, number of laminations, and individual differences during treatment can affect the results. Adverse reactions such as pain, erythema, edema and ecchymosis may occur. Microneedling is useful in treating depressed scars, but adverse reactions such as erythema and edema may occur. Patients who need to use microneedling to treat depressed scars should seek treatment in a regular hospital to avoid delaying their condition.