what to do 2 yr old fall and hit head

My 2 yr old fell out of the shopping cart (loud horrible sound). She was in the back (I know, and she will NEVER do that again)...our infant was in the carrier in the front. I did not see which part of her body she hit because the carrier was blocking my view, but she was holding her head. AFter giving her a bath tonight, I noticed a "soft spot" on the side of her head...very mushy. She has been acting like her nomal, busy-body self since the fall. Today, she was jumping on the trampeline, running around, and singing/talking like nothing had even happened. The soft spot is what concerns me. I will be calling her pediatrician in the morning, but I wanted to get any input on this. Thank you for your time.