While BP can go off feed for months it's important to remember that the animal is only 200 grams.
Here is what I would suggest if it's not done already, get some aspen bedding to put in the tub, don't offer food for a week and than leave a LIVE rat crawler overnight (right crawlers are big fuzzy rats that do not have their eye open)
If your snake has been consistent with eating (prior to you acquiring it) it will take rats again, if the rat pup was a one time thing he might still need some perseverance on your part to be completely consistent.