The board-certified dermatologist Dr. Doris Day has 242,000 followers on Instagram — and many of them are desperate to know how the 62-year-old has so few wrinkles and plump, smooth skin.

Dr. Doris Day, a board-certified dermatologist, has barely any wrinkles at 62. She has had cosmetic treatments but said anyone can have youthful-looking skin. Day's tips include using an SPF cream ...