Hello @hansong7, I would like to add my welcome to @colleenyoung and others. Fortunately for me I haven't had COVID yet but I do have small fiber peripheral neuropathy with only numbness and some minor tingling in the feet. Mine was diagnosed by a neurologist exam along with a few of the nerve conduction tests. I'm not sure anyone can answer your question of how far will it go. Each of us are different and in some cases if they can determine the cause and there is a good treatment they can normally provide relief for the symptoms. I don't believe there is any cure for neuropathy unless it's caused by a compressed or damaged nerve and it can be fixed with surgery - but that's just my non medical opinion from all the reading I have done.

One thing that has helped me is to learn as much as I can about my condition. There are two really good sites for learning about neuropathy.
-- Neuropathy Commons: https://neuropathycommons.org/neuropathy/neuropathy-overview
-- The Foundation for Peripheral Neuropathy: https://www.foundationforpn.org/treatments/

There is also another discussion where myself and others with neuropathy have shared our story and what has helped us -- Member Neuropathy Journey Stories: What's Yours?: https://connect.mayoclinic.org/comment/310341/

Did your doctor diagnose or think your neuropathy was caused by COVID, or have you been diagnosed by a neurologist?