Black bruises on the nail cap usually do not require special treatment if the nail is not separated from the nail bed locally, but can be treated by nail extraction surgery if the nail is already separated from the nail bed locally. If the nail is not separated from the nail bed, then no special treatment is needed. If the nail and the nail bed have been separated, then it can be treated by nail extraction. If there is black bruise on the nail cover and the nail is separated from the nail bed, then you need to keep monitoring the affected finger to see if there is any redness, swelling, pain, infection and inflammation. If there is any of the above, then you need to undergo nail extraction as soon as possible, and after the extraction, sterilize the nail bed, cover it with sterile dressings and keep the area dry and clean. If there is black bruise on the nail cover, please follow the doctor’s instructions for treatment.