Exactly. If that adventurer wanted to “cure” what he saw as a flaw, he could quest for a much more specialized magical healer or more powerful spell to enable it. I mention greater restoration, but true polymorph to his original form, or some kind of time manipulation, etc. There are options, at a high enough toer of magic, to undo injury, but that power has to have been attained.

This is why amputations aren’t cured by a cure wounds. You can’t just grow a pile of pork by hacking into a live pig and repeatedly healing it.