Funny you should mention a red blotch. I had painted a fist-sized area in the middle of my abdomen, above my navel & just below my sternum (I think this is mesentery painting). I did this a few times. The last time I did it, I had some splotchy redness that persisted for a while...couple of weeks? Not sure. It didn't itch or hurt. I can barely see it now. I kept forgetting to paint again & kept doing the internal consumption of iodine.