I didnt read the whole thread but read "yellow skin" and thought I would post my two cents in case it may help.
Iodine has helped my skin greatly. I used to get yellow skin too.
One symptom of low Iodine or low thyroid is yellow skin caused by lack of carotene conversion to vitamin A. Vitamin A is necessary for skin health/healing of skin.
Since starting Iodine my skin heals faster, no more yellow skin, no more cysts and the cysts that I did have seemed to melt away without coming to a head. My skin is smoother, softer, and glows whereas before it did not.
I tried vitamin A supplement and it didnt work as well though healing was faster.