Terry To use By Terry Cellularose Brightening Serum , start with a clean and dry face. Take a small amount of serum onto your fingertips and gently massage it into your skin, starting at the center of your face and working outward. Allow the serum to fully absorb into your skin before applying any other products. Once the By Terry Cellularose Brightening Serum has absorbed, follow with your regular moisturizer. Face Serums