Bump on the head

My son got his first bump on the head the other day. Now it looks like a rainbow, the middle is pinkish red, than a ring of yellow surrounds it, and an outer ring of green. When it happened my world stopped. He was running, and fell. It looked like he fell onto his little couch, so at first I thought he was fine, just scared. But he cried so hard. I picked him up and held him, we spun around the room and sang. He was happy again. Then I saw the bump, big raised bump with a bruise on top. We took a picture to see if we needed to take him to the doctor. It probably looked worse than it was, but to me it was as if he had been wounded in battle by an ax.