Like I said, it's under the same category as Chopper drawing blood from Queen but later saying he hasn't hurt Queen. The character statements matter more here and any hypothetical regeneration you wanna give King doesn't jive with the fight itself. It was about bypassing King's toughness not regeneration or anything.
I don't care about giving King healing—I am saying he retconned it meaning I am admitting he dropped the idea. It won't be a bigger boost than a defense superior to Kaido's anyways. I am trying to explain what actually happened while you're trying to rationalize an obvious mistake on Oda's part. Oda retconned his plans for King—He probably didn't want to give KIng a superior defense to Kaido and changed his mind later on.