Ok, he's a pretty young snake, but I can't say that anything screams wrong with your husbandry. I would just get that probe so you can always know how hot his hot spot it. Just good to know and not guess that sort of thing.
Just a few more questions, does he sit in his hide all day, or have his body in with only his head sitting out of the entrance? Or does he hide somewhere else or move all around?
Just trying to narrow some things down. Also, what time of day do you offer prey?
This is my suggestions for certain answers:
If he does not hide all day, chances are he is stressed out. To remedy this, you can fill his tank with crumpled newspaper, papertowel, decorations etc. Anything that he can feel on all sides when he's moving around the tank. It may not look pretty, but security is number one with babies BP's.
Stuffing his enclosure will help him feel safe, you will be able to remove a piece at a time over the weeks as he continues to eat.
Go to a pet store and get some soiled rat/mouse bedding. Whatever you happen to be feeding. Put the frozen mouse/rat in a paper bag/ tupperware, anything that you can poke holes into that he can't get into. Put that into his enclosure an hour before he's going to eat, around 8:30-9 at night.
Make sure to leave him alone, you could even cover most of the front of his enclosure with paper or a towel to make it dark for him while your thawing the rat.
When it's thawed, probably around 9:30 pm, pull out the rat/mouse and bedding and heat the head under your heat lamp. Make it warm, so he has no trouble seeing that heat when you offer it.
Make sure it's quiet, dark, and offer him the rat/mouse. Do the zombie rat dance, make it twitch a little, get him interested in it.
When he strikes and has a good grip, tug the leg like the rat is kicking a little, he should tighten up his coil and get really into feeding mode.
If he does not strike, do not despair, leave him alone in the tank with the prey for a half an hour, pull out the rat again, heat up the head and offer again. If he resists your attempts, leave the rat in the cage over night. Check on it in the morning.
If it's gone, congrats, if not, try the exact same thing next week. If he continues, you may have to resort to live.
Hope that made some sense.

Let me know how it turns out.