2-3 days. According to the query of China Doctor's Network, use iodophor to disinfect the wound, use iodophor or alcohol to disinfect it, and then use iodophor gauze to protect the wound, or use alcohol gauze to protect the wound, or directly cover it with sterile gauze to keep the wound clean, dry and breathable to avoid secondary infection. Therefore, it takes 2-3 days to change the dressing of the needle wound.