First of all, do you have a less visible spot upon which to experiment so that you can familiarize yourself with iodine painting? For instance, I removed a suspicious-loooking mole years ago by painting 5% lugol's on it. That process involved repeated painting. The mole absorbed the iodine, it dried up, raised up and fell off. I would paint oh I guess 3 or 4 times a day. The entire process took a week- 10 days or so. This was on my arm, though, and it was a mole.
A friend of mine removed a keloid from her ear using the same process. That took a few months as the keloid was quite large.
We have had many, many experiments with iodine painting here:
I wish that I could tell you that of course your scars will heal and normal tissue will present. I can't do that...
You will have to research this subject and make a decision.
People have used various means to enhance absorption of iodine including castor oil, other oils, abrasion and dmso. I formulated an iodine cream and salve to provide slow release of iodine to the skin.
If I were you, I would work on my general health first, including an elimination diet to find out what foods may be triggering your skin condition. Seborrhoeic dermatitis can be indicative of hypothyroid as well... no doubt you need iodine, we all do... :)