The humidifier did not cause the problem (unless it blew cold mist... in that room it could have done so). It's the combination of conditions that works, not one thing which even makes (the cold) things worse. If you humidify a tropical, you need to keep it warm, or it'll think it's getting snowed on. Anyhow, take care of the temp. and the lighting, DO rig some way of humidifying (like the trays I described, not the machine) and hopefully it will recover with new growth, but it could take weeks, so just be very patient, don't move it around a lot, and wait.