Benadryl for Ruby- Day 2

So I gave Ruby her second dose of Benadryl, though her first for the day. I was having no luck with hiding it in treats or pilling her. So I tried peanut butter. I was really against using peanut butter since Garrett has allergies to peanuts and I am not sure how sensitive it is. My thinking is that I use peanut butter 5+ hours before he gets home. That way the peanut butter should be out of her system and out of her saliva. So I figure that by the time he gets home and she can lick his face, it should be safe.