my son fell of the top bunk about 4 hr ago. he is 4. he was crying for a while. I checked his eyes to see if they would dilate. They did. He has not had any nausea. I let him go to sleep after 3 hr. I woke him up. he was hard to wake up. He started playing again and after about 10 min. sat down and began crying stating his head was hurting. I sat him down and he seems to be doing okay. should I take him to ER