yea it will cause burn spots if u using hid lights and if the spray aint a fine mist, cut some crappy leafs off if u want they aind much use now, all they doing is blocking light that better leafs could be using,, dond get a bit chop happy dont take to many at a time, i dont like to remove leafs at all until they fall off them selfs, but when i have took them off for a reason a only take about 2fans a day, and only the worst ones on the plant
peace