My seven year old daughter was running down the hallway and ran into her room and hit her head on the facing of the wall near her closet. She started crying right away and I picked her up. I looked at it and it was red near her temple where she hit it. She cried for 5 minutes and then got okay. She said 30 minutes later her head still hurt where she hit it. She is laughing and playing now so should I be worried. What should I look for?