Thsnk goodness you rent- bad problem but your concern is your health,mold is hazardous- you can request your landlord test for mold that it be addressed appropriately,may have to tear out some sheet rock etc.....Wondering what to do about all the mold in our apartment. The bedroom window gets all the moisture and not the others because the others are on the balcony so they are protected. But the bedroom window now has mold because it is exposed and so is the little AC vent they have in the wall. I don't know if it would be possible to seal it up. My partner and I got some bleach to put on it but I know that if the moisture issue isn't dealt with, it'll just come back and be a pain. Water sometimes drips from the window and the AC vent and down the walls. We could ask building maintenance I guess but it's an old building so not sure what they can do about it. Ugh.
I do hope it is resolved quickly- straight undiluted vinegar kills mold- soak with vinegar ( spray bottle) let vinegar sit at least an hour before you wipe with warm water- then repeat
It's possible to kill mold with bleach but not as effective as vinegar which kills at the root so it unlikely to return( plus bleach is so toxic( kitties)