Apply the NUMBUZIN No. 6 Deep Sleep Mask Pack Serum as the last step of your evening routine, after your cream. Spread a small amount over your entire face, avoiding the eye area, then leave it on overnight like a sleeping mask. Do not rinse: it works while you sleep to leave your skin plump and refreshed upon waking. Use it 2 to 3 times a week, or more often if your skin is very dehydrated.