When we walked into his classroom to pick up his backpack and coat so I could take him home he gave a hearty fake cough to call attention to himself, put on his saddest face and then pulled away the ice pack slowly for dramatic effect to reveal his goose egg. It totally worked - he was rewarded with resounding "ooooooh!"s and "owwwww!"s from his classmates.
By the end of the day it was just a nasty looking bruise and Hubba was happy for the time spent at home watching movies and showing off his injury to his siblings.