Ah, first snake stress. Fears of scale rot, humidity, temps, why isn't he shedding worry, worry, worry. I remember that. In fact I still go through it whenever I get a new addition! Snake keeping is a practice. Do your research, read, ask questions, but at the end of the day your own experience will be the best teacher. It sounds like your off to a strong start.

Looking over your thread, you're set up for a long hard fight with humidity. The aquarium/CHE combo will hamper you at every turn. My balls have shed issues if humidity is less than 65% or so. I have a BEL who will have a bad shed in anything less than 75%. As a solution, when I see their eyes cloud over I create a micro-climate monsoon season, it practically rains in the terrarium until I get a shed skin. You obviously can't achieve this with a glass aquarium but there are steps you can take. Somebody above suggested a humidity box, which can do wonders. Get a small opaque Tupperware container, big enough for the snake to have a tight fit, cut a smallish hole, just big enough to allow tight access, layer damp sphagnum moss inside and place it on the warm side. If you don't like sphagnum moss, you could use some damp coconut substrate. It might be a little late now as the BP is already in blue and most snakes don't like new things, but maybe worth a try.

Since the BP is already going into blue, be prepared for him to clear up rather quickly. They only look blue for a day or two, then return to normal and look better than ever! Lots of first time keepers make the mistake of thinking they missed the shed. It can take up to a week for the entire process to play out. Keep the terrarium humidity as high as you can until there's a shed in hand. Since you are having so much difficulty with humidity, keep and eye and consider that the shed may not go perfectly. It's not a crisis if it doesn't, and any stuck shed can be addressed. When my BEL shed for the first time all she got off was her head, the rest was fully retained. I was horrified, but after 20 minutes in a lukewarm bath (water was 80 F) I was able to assist the shed and it came off. She then pooped on my hands by way of thanks.

Try not to stress too much and enjoy that gorgeous animal. Bananas are a great morph and tend to age very well. Keep posting your progress, and enjoy your snake!