The reason he still has the inane training weights on his body even during the whole battle (which is one of the reasons he struggled so much without help) is because he needs to reconstruct his body a second time, something not even the previous heavenly demon was able to do. The poison is slow acting if he limits the use of his internal energy, but he is living on a timer. With the war finally over, we'll likely see his progress on the martial arts for a second body recustruction and when it will be possible. I could be missing info but I have a lot more on my mind because I had put this series on hold and just binge read a bunch of chapters.

Hey hey hey, don't talk like that or he will get poisoned soon, talking like this is bad luck my man

he fixed that problem many chapters ago