If you are not going to take Iodine internally, there is no need for supplements.
If you should decide to take it internally the minimum required supplement is selenium 200mcg a day. All the other co-supplements are to help detox & to aid in the Iodine symporters.
Caution, be very careful to keep Iodine away from your good skin & focus in only on your bad skin. When I used iodine to get rid of a cancer lesion, I used a pencil eraser to apply the iodine so it wouldn't spread to the good skin. Does anyone have a better idea to keep the iodine from dripping off the spot?