Head collides with knee, or Prop falls on ankle.
At first, you walk it off, "I'm okay, I'll just ice it when I get home."
The next day you have a basketball for an ankle. Black and Blue, you know you broke or tore something.
What to do?
SEEK MEDICAL ATTENTION ASAP...
Some plans could deny a claim as non-emergency, or non-accident, because you waited to see an MD. Yes, it sucks, but that's the law.
So, when it doubt, kick to a medical professional.