What are the health consequences of taking high doses of iodine when one has a thyroid cold nodule in the neck

Kelp is a seaweed that naturally contains high amounts of iodine. I have been taking 1 capsule a day of supplement made from Kelp that provides 400 mcrograms fo iodine- which is 267% of daily recommended value.
I am hoping this will shrink my thyroid nodule.
Otherwise my blood work shows a normal level of thyoxine.
What if any are possible side effects?

Thanks