Here is Dr Myhill's article on Lugol's iodine. The way she talks about it makes it sound incredibly safe.
And here is a website she links to which talks about it further.
Iodine is another tool that has revolutionised my practice! Like Vitamin C it contact-kills all microbes. It is the only agent that is consistently active against gram positive and gram-negative bacteria, mycobacteria, spores, amoebic cysts, fungi, protozoa, yeasts, drug-resistant bacteria such as MRSA and viruses. In the doses below, it is non-toxic to the immune system cells responsible for healing and repair – indeed studies show it enhances healing. This is why the surgeons love it. Skin painted with iodine before incision does not get infected and heals perfectly.