"Undiluted Lugol's is caustic and may cause blistering of the skin and/or itching which is problematic for ear use but seems to cause no permanent damage."
There's something else at play re: Lugol's causing blistering, etc. When I removed a mole with lugol's, I also painted a healthy mole and a patch of clear skin for comparison. Control areas absolutely unaffected by the lugol's.
Quite a few people here have painted their faces with lugols, search "paint" or "painting" within this forum...