Scar removal injections generally involve localized injections of tretinoin, betamethasone, 5-fluorouracil, etc., into hyperplastic scars or keloids, with local anesthetic medications occasionally added to prevent pain. So the dangers of scar removal injection include drug allergy, skin atrophy, bleeding and infection. 1. Drug allergy: a very small number of patients may be allergic to the injected drugs, the less severe may appear redness of the skin, itching, pain, etc., the more severe may appear laryngeal edema, shock and other life-threatening conditions. 2. Skin atrophy: local injection of glucocorticosteroids to remove scars, if the injection site is shifted, may make the healthy skin next to the scar atrophy. 3. Bleeding: In the process of scar removal, multiple injections will be given at multiple points along the scar, due to the scar tissue is brittle and rich in capillaries, there will be relatively more bleeding during the injection. 4. Infection: after the scar removal injection, there are more needle holes around the scar, bacteria, viruses and so on may enter the body through the broken needle, causing local infection, and in serious cases, it can cause systemic infection. It is recommended that patients under the guidance of a doctor to play the scar removal injection, discomfort, immediately go to the hospital, to avoid delays in the condition of the adverse consequences.