I got a couple of deep bruises when I was a kid and they really hurt a lot. I do remember that I was always quite happy to have and show off the colors of the bruise though. In fact I remember that there were a few of us in one of my classes who were always willing to show off the scrapes and cuts and bruises we got from sports or from climbing trees or whatever.
It would gross out the girls and impress the boys. Of course, a healing bruise actually looked more impressive than a fresh one, since it would have more colors!