Melanin deposits left by skin allergies generally refer to post-inflammatory hyperpigmentation, and patients can lighten the pigmentation through medication and physical therapy. 1. Medication: patients can use drugs that inhibit melanin proliferation, such as azelaic acid cream, hydroquinone cream, etc., or retinoic acid drugs, such as retinoic acid ointment, adapalene gel, etc., under the guidance of doctors. After drug treatment, melanin deposition can be reduced, so as to effectively remove the local skin melanin deposits. 2. Physical therapy: some patients can also take laser treatment, through the photothermal effect, so as to lighten the melanin deposits, to remove the role of melanin deposits. During the treatment period, patients with melanin deposits left by skin allergies need to follow the doctor’s instructions for regular review, so as to understand the recovery of the disease.