I went through a period with pretty annoying numbness that developed in my left hand, specifically the bottom two fingers. It was clearly ulnar nerve related, and I bought a flute with an offset LH3 hole which helped, and have turned the middle section on both my flutes away from my body, which also really helps by keeping the left wrist straighter.
Nerve inflammation can take much longer than you expect to improve, but avoiding the things that lead to it can solve the problem. Also avoiding a death grip on the flute can help.
I think the Larry Nugent hold requires either a freakishly long thumb or a differently placed G# key than I have…just tried it, can see some advantage to it, but with my G# key, owww…it’s really painful.
Eric