Jenny Liu, MD FAAD , Skincare expert on Instagram: "Always good to revisit how to apply retinoid especially with winter upon us! Sandwich method if you’re newbie or have dry skin Traditional methods if you’re more of a pro Using @firstaidbeauty ultra repair cream to finish and @charlottetilbury magic water gel cream for First Layer of sandwich Which one do you use? #retinol#retinolskincare#retinoid#tretinoin#skincarehacks#skincaretips#skincare101#derm"