M.F.
When I have a question about medicine I always ask the pharmacist they are a lot more knowledgeable about dosing/medication and are super helpful. He could have Benadryl that young but you need the correct dosing and I only give medicine as absolutely necessary as there is always a risk for a reaction and it's good for the body to build its own defenses. To be it sounds like wind blown I would just put some lotion on it.