I saw stars like this right after I fell off the jungle gym at grade school and landed on my head on the cement. That was back before they put sand or wood chips underneath playground equipment. Mr. Daniels said I bounced three times off the cement and put a crack in it. They tried to bill my folks for repairing the cement, but Dad told them that they should have known better than to let my head anywhere near something as fragile as cement. They made me start wearing a helmet at school to protect the cement.
Did you have a problem with door handles, too?