Try a light foliar spray then after it soaks in put your fan on a higher setting to make sure the plants dry out since you have some early flowering going on. It won't solve the problem but may help you identify it so you can increase whatever it is they are lacking. You can buy cal/mag/zinc vitamins at any store, crush them up and use them in a foliar spray this way you have isolated the nutes. The leaves won't repair themselves but should prevent further symptoms.