You need to take a higher dose, the Acne was "bromide acne" and you were detoxing. The fbd is from bromides taking up residence in the Iodine receptors there.
Salt loading (1/4 tsp in water --big glass so it only tastes mildly salty, or get a capsule filler, empty gelcaps and put the salt in capsules) with unprocessed salt and liver supporting supplements like milk thistle and/or N-acetyl-cysteine will help reduce and clear up the bromide acne. Taking the companion supplements help repair the Iodine symporters and help get the Iodine where it needs to go.
The acne, btw, was evidence that you were detoxing and the iodine WAS displacing the bromide. Keep at it, and keep taking 100mg if you can tolerate it 'cause it will get rid of the fbd quicker than a lower dose. Pulse dose (stop iodine) but keep taking the companion supplements (see link below) and salt loading if detox symptoms get too bad.