2024 5E’s Resting Rules and Greyhawk’s Regions! (MD 207)

999.818 - 1023.864 Sean Merwin

And I'm going to give an analogy that's not perfect, but I think gets part of the point across, which is this. To answer the question about why you can't heal or cure disease or cure exhaustion with the medicine skill, it's the same reason why you can't create balls of fire that damage creatures with the arcana skill. Because there's already other ways that the game expects you to do it.