Why close How deep into the skin does topical Benzoyl Peroxide penetrate? as off topic, when How deep into the skin do topical acne medications penetrate? isn't? The former is a hyponym of the latter.
Did you read the reason given and the links it points to? A comment was posted informing you of the problem 6 days before it was finally closed but you never responded. You have some nice drawings of skin layers but nothing more and nothing about the drug you're asking about.
You can fix the problems by editing the question to tell us what prior research you did. What did your research reveal and where did you find it? If you found nothing, what did you search for? Add that and the question becomes eligible for reopening.