myroro
I have developed rashes due to liver flushing. It does release and stir up toxins. Since yours appeared before the actual flush, however, this doesn't seem likely. It looks more like a reaction to the hot water bottle, given its location and appearance. Most likely, it is due to a combination of the salts and the heat of the bottle.
On the whole, I would consider it a good sign. Rashes are almost always a symptom of toxicity, and you seem to have started something moving.
Continue to flush at appropriate intervals.