If the nail cover is pinched with black blood, it depends on the specific situation (e.g. the amount of blood, the time of being pinched, and whether it is accompanied by edema, or the broken condition of the nail or nail bed). 1. In general, if the amount of blood is not much after being pinched, the blood can be absorbed and disappear on its own without special treatment. 2. If it is not long after being pinched and is accompanied by edema, ice packs can be applied first. If it has been some time since being pinched, and if black blood has appeared as mentioned above, hot packs can be applied to help dissipate the bruises. 3. If there are obvious broken nails or damaged nail beds, it is recommended to go to the hospital for debridement and bandaging, and treatment and medication should be carried out under the guidance of the doctor.