Once upon a time, when I was a younger girl than I am today, I got poked by a cactus on my leg. I examined my wound and determined that the cactus spine must have fallen out, as I did not see any evidence that the spine remained. Months passed. One day I noticed I had a swollen lump where the cactus had poked me months prior. When I pressed on the lump, it was painful. Something hard and pokey was just beneath the surface. At first, I thought I could ignore the lump and it would just go away. Alas, this strategy ...