the hot, steamy water with Vicks and oils is supposed to help w/ breathing but will increase humidity - so only do it for like 10-15mins per session for only like 2 times a day. personally i would just keep the humidity normal and where it is once u get antibiotics.
just be on top of husbandry. u coulda missed a spot to clean here or there and/or the the recent high humidity for a few days could of added to the bug.