Yes, I have studied and traveled the Iodine path before in a form of self experimentation.The palms of the hands and the buttock both have highly efficient absorption and shouldn't sting at all in those locations.
While my topical application was brief and limited. I experimented with ingestion of Iodoral tablets. I was only able to reach the 50mg mark, where suddenly and without warning I developed severe IBS-D to which I had never experienced in my life.
I ceased all exploration of Iodine at that point.
I would suffer the consequences for a year until a 10 day administration of ciprofloaxion resolved the IBS-D issues I had after my Iodine experiment. I would later pay the consequences of this particular antibiotic likely attributing to increased nerve damage I had in my hand at the time from a previous injury, to which I would eventually have surgery for and fortunately have completely recovered from since.
From what I can gather, potassium iodide is perhaps a safer form in and of itself. But not sure I will be crossing paths with supplemental iodine any time soon but I still find it quite fascinating.