In nothing changed recently, 1 dropper full is 200mcgs, not 20.
I'd measure out with a syringe, for the burn at least. I measured-out 1 ml in a syringe one time, put it back in the dropper and made a mark on the dropper, that way I knew how much 1ml was each time. Believe it or not, you usually pull out just about 1 ml each time with a regular pinch.