In case you've never tried it before, let me assure you that It's really hard to take a picture of your back. I had to use a mirror to make sure that the camera was actually aimed at me and not at the wall behind me.
Yes, that splotchy red expanse of skin is my right shoulder and back, and no, I was not injured in some horrible accident. Or rather, I WAS injured in some horrible accident, once upon a time, and the gross bruising is evidence of that. It's just that the injury is old, and the bruising is recent. Also self-inflected.
See, I was employing a technique called gua sha (read all about it in a Wikipedia entry or at a website called Gua Sha), which I LOVE both because A) it works and B) I can do it myself--at least on some parts of me.
As the links I've included explain, the idea is that some sort of trauma or illness leads to blood stagnation in areas of the body. To heal an imbalance, you induce "extravasation of blood from the peripheral capillaries," which looks horrible but doesn't hurt nearly as much as, say, an intense bout of physical therapy, and can actually feel GREAT. It soothes muscles, releases tension, and, some people claim, repels colds.
Here's what you do: rub the skin with some sort of lubricant--Tiger Balm or Vicks VapoRub work well. Take one of those Chinese soup spoons and use the long edge to scrape the skin. If there is grossness, a group of red bumps will begin to appear. The worse the congestion and stagnation, the more intense the redness. If there is no congestion, you can't get any weird redness to appear, though you can give yourself an old-fashioned purple bruise if you scrape too hard.
Depending on how deep and intense the stagnation is, it will disappear in anywhere from one to ten days. The first time you do it, the bruising will take longer to disappear, because it's had so long to accumulate. If you do it periodically--say, every six months or so--the bruising will fade very quickly (a day or two) unless you've suffered a major injury.
Ideal spots for the technique are shoulders, neck and upper arms. It's especially good for combating the muscle fatigue and tension involved with sitting at a computer for hours each day.
Seriously. Try it. Or better yet, find someone who is familiar with the technique, and get them to do your entire back for you. You won't want to parade around at the beach right after that, but you'll be glad you had it done.