People will say "open up the headlight and dry it out", but that's not a quick thing with these headlights and they're not particularly accessible without removing, which requires taking off the front bumper. I wonder if you have a crack somewhere causing this. This Reddit thread might be helpful:
https://www.reddit.com/r/BmwTech/com...get_rid_of_it/
Might want to check eBay for a used replacement; at least you don't have the laser lights, which are more expensive.