Hello @gflandre62, Welcome to Mayo Clinic Connect. Short answer to your question does an injection of Wharton's Jelly cure neuropathy - Nope. I have no medical training or background like most of us but I have never seen, heard or read about any treatment that will cure neuropathy. There are a lot of treatments that relieve the symptoms of neuropathy (pain, tingling, numbness, etc..) but nothing cures it.

The one caveat (in my opinion) is if the neuropathy is caused by a pinched or damaged nerve where it can be fixed by surgery or other treatment such as Myofascial Release Therapy (MFR). There is another discussion for MFR therapy here:
https://connect.mayoclinic.org/discussion/myofascial-release-therapy-mfr-for-treating-compression-and-pain/