The most common for having scratches when you wake up is self-scratching. Allergies or dry skin may cause you to feel itchy and scratch to ease discomfort during the night. In some cases, you may also scratch yourself accidentally when wearing jewelry during sleep or having too long nails. Self-scratching injuries tend to be mild and only require minor treatments. For bleeding scratches, make sure to cover it with bandages. To prevent this problem, try to keep your nails short, keep the skin moist and hydrated, as well as remove any uncomfortable clothes or jewelry before sleeping.