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.
My now 18m child fell off the couch, about 8 months ago and bumped his head on hardwood flooring. He had a nice goose eggon his forehead for a few weeks. But then about 3 months ago he bumped his head on the corner of the wall in the same spot. The lump is still visible, especially when he raises his eyebrows.