Well, if it doesn't create potential for serious illness or injury, then it probably doesn't matter. But, if you're doing any type of serious self-injury, the chances are there are some potentially serious complications that could develop. And, here again, if there's no one in your life who cares about you, & you don't care, then I guess you're correct... it doesn't matter. But, in most cases, individuals have someone... a family member or a friend who want to keep you safe. Also, while you may feel that it doesn't matter now, in the future you may regret whatever permanent damage you may have done to yourself... (I speak from experience...)