he was actually trying to heal himself, he just didn't manage in time for later
Just curious – do you mean that he was trying to heal himself the whole time to the end, and blowing up Ye Zun was just a happy coincidence, or that he was trying to heal himself in the kitchen, but later changed track to turning himself into a brother-killing bomb? (Given how he acts in later canon, there is at least some support for the latter option, even if the plan is a bad one, imo.)