I once bit my lip really hard and it swelled up. I then bit it again the next day in the same spot because it was so swollen. And then again the day after that. It healed over a spit gland and I had a massive growth in my mouth for like 2 months before I realized that it wasn't going away and having to chew using one side of my mouth kinda sucked (that sucker stuck straight between my teeth so bit it a few more times after that). Had laser surgery to cut it out that only took like 15 minutes or something.
Also my sister and I thought it would be a great idea to pull me around on a blanket on a polished wood floor next to a table with sharp-arse corners when we were kids. I slipped and hit my chin on the corner. Mother was not happy after that hospital trip. Only required those tiny sticker things and not full blown stitches though.
Also holy fuck the number of guys on tf.tv who're missing balls or have had testicular complications is alarming.