High humidity.

Well the easiest method is to get a dehumidifier. Don't waste money on a small, cheap one, they dont work well. Other things you can do is increase airflow in your grow space. For a tent, an inline duct fan is key. Otherwise, you can add a couple oscillating fans to the area. This won't bring down the RH, but the high airflow helps at warding off molds and mildews. Last option is to defoliate. Defoliate the bushiest part of the plant. This will decrease her perspiration so helps with RH. It also opens up airflow, again, important for keeping molds and mildews away. All that said, a few days at a high RH won't kill her. Just make sure she has good airflow. Best of luck my friend!