Aichun Beauty Vitamin C Essence Facial Mask. This popular mask is infused with the goodness of vitamin C, promising a brighter, more radiant complexion the mask typically comes in a sheet format, making it easy to apply. Simply cleanse your face, unfold the mask, and press it gently onto your skin. Relax for 15-20 minutes, then remove the mask and massage any remaining essence into your skin. The mask often contains other hydrating ingredients like hyaluronic acid, leaving your skin feeling plump, smooth, and refreshed