Somewhat inspired by organizedcrime 's question:
Did you ever have an injury that you thought was 'no big deal' but was actually more serious than you thought? Did it end up hospitalizing you or causing an infection or something else?
Many years ago, I slammed my finger in the door of my father's car getting out to go to school. My entire nailed turned black from the blood, and I tried to put up with the pain. It hurt too much, so I finally went to the nurse expecting some tylenol and an icepack, but she ended up calling my mother to take me to the hospital. The doctors said the laceration in my nail bed could clot and something bad would happen to my finger, so they took off my nail, stitched the cut in my nailbed, and then stiched my nail back on. If I had not gone to the hospital, something more serious would have happened. But I mean, stiches for getting your finger slammed in something? It was kind of crazy.