Is he being fed live? Almost looks like a bite or something, plus his neck is a bit swollen which made me think either injury or RI. Maybe it's just looser skin and he's sitting funny, hard to say without seeing it. Has a vet seen him? Might need a culture run.
Tail tip not shedding is somewhat common coming from a bad humidity situation, heavy misting on it like you are doing is a good thing. If it doesn't come off in the next shed, you'll need to intervene and soak or damp towel sauna and get it off for him otherwise the old shed can constrict the tissue at the end of the tail and cause the loss of the tip plus possible infection.
Dealing with a larger snake can be intimidating, especially if you haven't done it before. Luckily he sounds pretty calm so far. Try using a shield, like the top of a rubbermaid tub, use one hand to hold the shield between his face/neck and the rest of his body and use your other arm (or a helper) to lift his mid section out, lift from the bottom/belly. He'll probably scoot forward, sometimes it's like grasping a giant slinky. Just be calm and sure of your motions, don't grasp or hold tight. A hook can be used instead of a 'shield' or even a roll of papertowels! I simply mentioned a shield since it can make you feel quite secure he won't be able to whip back and bite you. That is what I do with overprotective momma snakes that just had a litter.

Good luck with him! Keep up the good work!