A 16-year-old boy is brought to clinic for worsening facial lesions over the past 6 months. He has numerous erythematous papules and pustules with several closed comedones on the cheeks and forehead. He has been adherent to a nightly topical retinoid and daily benzoyl peroxide wash for the past 10 weeks without meaningful improvement. He is otherwise healthy and takes no medications. Which of the following is the most appropriate next step in management?