Fine lines and wrinkles are signs of skin aging, appearing as creases, folds, or lines on the skin. Fine lines are typically shallow and first appear around the eyes, mouth, and forehead. Over time, these lines can deepen into wrinkles due to factors like natural collagen loss, sun exposure, facial expressions, and environmental factors. While fine lines are an early sign of aging, wrinkles are more pronounced and can appear on various areas of the face and body as the skin loses elasticity and firmness.