Body Mass Index (BMI). Body Mass Index (BMI) is measure of body fat based on height and weight that applies to both adult men and women. BMI does not differentiate between body fat and muscle mass. Therefore, body builders and people who have a lot of muscle bulk will have a high BMI but are not overweight or obese.
The bump: or hematoma as we call it, can last for 1-2 weeks. Sometimes it gets slightly worse before it gets better. If the child is acting normally, and not vomiting uncontrollably, she should be fine. If she starts doing those things, call your pediatrician.
I had a concussion 3-4 years ago, the bump on my head had a grapefruit size back then... i never went to see the doctor, about 6 months ago i start having sever headaches they last 4 weeks or so, I've notice that every time i feel sick the bump in the back of my head has this jelly-water weird sensation (to the touch).