SMALL BRUISE ON UPPER ARM

On Tuesday, October 25, 2011 I found this 1 x .5 inch oval-shaped bruise on my upper inside arm about 3 inches from the underarm.

It hasn't hurt at all, no raised surface, and was 20% darker by Wednesday. I didn't bump my arm, and no one grabbed me as far as I know.

This is at least the third or fourth bruise I've found in four decades that I couldn't explain how it got there. Picture was taken today (Oct. 27).

MARKS ON MY UPPER BACK (LEFT SIDE)

On October 13, I found a fresh set of four marks side by side on my upper back on the left. It was very difficult to take a picture of it myself, and my new camera not the best image render.

Here's my account of it at MissionQuest Forum:
Pin Dot & Scoop Marks, & Other Mysterious Body Markings

These pics were taken this morning (October 16, 2011).
As you can see, the scabs have already started falling off: