I remember Kobe and others doing that back in the day. I believe the NFL has a clause where you can forfeit guaranteed money and get put on the NFI list for doing that, though, if the surgery complications from an unauthorized procedure such as that led to further damage or complications.
That said, it's a ing joke how horrid the USA healthcare system is, and the FDA, NIH, and CDC are all a ing joke. Laughingstock of the world to have "muh #1 economy" but be ranked a paltry 47th out of roughly ~200 coutries in terms of life expectancy, so barely even top quartile. Right to try has always been a Trump principle, like him or not, but no, big gumment gotta decide what we can and can't do with our bodies here in the USA.