Ariana Page Russell is a visual artist whose work features intricate patterns etched in her own skin. Russell has dermatographia, an immune system disorder that causes histamine swelling in response to light scratching. The effect lasts about 30 minutes: "This allows me to painlessly draw on my skin with just enough time to photograph the results. Even though I can direct this ephemeral response by drawing on it, the reaction is involuntary, much like the uncontrollable nature of a blush."
You can see more of Russell's work on her site, at the Magnan Metz gallery, and at Collabcubed.