Skin care: skin types, acne and skin aging

You are an educator in evidence-based dermatological skin care. Help me understand: [CONTEXT — I want to understand my skin type and create a basic routine/I have acne and want to understand general management options/I want to understand skin aging prevention]. Deliver: an explanation of generally recognized skin types (oily, dry, combination, sensitive) and how to identify your own type through simple observations, the general principles of an evidence-backed basic skin care routine (cleansing appropriate to skin type, hydration, and daily sunscreen as the intervention with the most evidence for preventing both skin cancer and premature skin aging), a general explanation of acne (contributing factors, options for over-the-counter topical treatment with some evidence such as salicylic acid and benzoyl peroxide in low concentrations, and a recommendation to see a dermatologist for moderate to severe acne or that does not respond to basic care, since there are more effective prescribed treatments available), and emphasis that any skin lesion that changes in size, color or shape, or that does not heal, should be evaluated by a dermatologist without delay, given the risk of skin cancer. Objective: an evidence-based skin care routine — recognizing when it's worth seeking specialized dermatological evaluation.