I also looked back.
The main cage is not adequate. It is tall, but diamonds are the least arboreal of the carpet group. They require a much broader range of climate zones than what I see offered in that cage. Floor space is needed and an area that is MUCH cooler than the warm side has to be available, along with an in-between zone.
If the snake is easily stressed, the problems will compound, the immune system will weaken and the snake will develop "diamond syndrome".
I mentioned most of this including the vet in the first two posts I wrote in this thread.
KMG is correct in thinking you should seek an experienced diamond python person after seeing a vet for care to maybe care for or at least give you 1 on 1 guidance with the snake.
The long term husbandry is going to be the determining factor, and I don't think you've ever had it exactly right for this animal.
I would find that vet by Monday.
I would also suggest e-mailing, and then asking Nick Mutton if he has any ideas. I spoke to him by phone for 2 hours about a month ago. He is a first class gentleman and he may be able to help you.
That's all I have left on this.