My eight yr old son tried to climb on his seven yr old sister s shoulders while at a water park, and he fell and bumped his head on a concrete step. That was at six o clock. At eight-thirty, just before he went to bed, he had a very noticeable bump behind his right ear. He complained of a touch of nausea just after six, in the car on the way home, but nothing again after he mentioned it that once. At home, before bed, he watched part of a movie and ate some food. Should I wake him up and take him to the urgent care center to be seen, or is he probably fine? (I ve started all of my google-ing after he s gone to bed, and now I m getting increasingly more worried,)