My son is 15yr old and otherwise extremely healthy. I noticed he has 2 bruises on his lower back, right at the L3 and L4 area. They are very dark bruises and we can't figure out anything he had done to get them.
He sits at his computer desk a bit hunched but that area does not come in contact with any part of his chair.
My concern is if there is something internally I should be concerned about?