A scalp hematoma is a collection of blood under the scalp skin after a bump, blow, or hair-pulling injury. It looks worse than it feels, but knowing the signs keeps you calm. The first thing you notice is a soft, squishy lump that appears within minutes. It may be cherry-sized or cover half the head, yet the skin can slide over it like a water balloon. Pain is usually mild and throbbing. Over-the-counter painkillers calm it, and resting the head on a pillow feels better than sitting upright. Skin color changes follow the clock: red-purple at first, then blue, green,... Learn more