That may be mold not trichome development, best to keep the night temp within ten degrees of day temp to prevent mold.Never heard of making things warmer being good except when running CO2. Now one thing I do know from experience is colder temps at night can help enhance trichome developement. One of the things the resin does is help insulate the plant from cooler temps. So making it cooler at night (to a point) encourages the plant to insulate itself better. What I do is I drop my temps to 60 degrees F and drop my relative humidity to 30%. Just during flower and just during lights out. Lights on and it's 75 to 80 degrees with an rh of 50%