When I was about 9 someone shoved me on to the blacktop as we were running in from recess and my right knee was just demolished.
For months I picked at the scab. I had a huge scab on that knee all summer because I wore shorts every day and could never stop picking. When school started in the fall and I was back to wearing pants my knee finally healed. There is a big puckered scar that reminds me of what happened, even though it's been 20 years. But there's also a lesson there too. Sometimes (not in your case though) terrible things happen and we need to ignore them after they've happened so we can heal.