Band-Aids are needed for wounds at night. When there is a wound on the human body surface, it is prone to bacterial infection. The main ingredient of the band-aid is benzalkonium bromide, which may also contain some other pharmaceutical ingredients. After the band-aid covers the surface of the wound, it can effectively prevent bacteria from invading the wound and avoid wound infection. The band-aid needs to be applied in 24 hours, during the day and of course at night. If you don’t put a band-aid on at night, it can lead to bacterial infection of the wound, redness, swelling, pain, and even pus flowing from the wound. If the wound is infected, you need to go to the hospital outpatient clinic to change the dressing, remove the sutures on the wound if necessary, use hydrogen peroxide or iodine povidone to disinfect the wound, and take oral antibiotics.