A topical formulation of Pirenzepine 4% called WST-057 is currently undergoing clinical trials for diabetic PN. It has completed phase 2b trials. Will be several more years to complete phase 3.
From what I have read this cream could greatly help, even regrow peripheral nerves.
WinSan Tor has a Compassionate Use Program you can sign up for. Doesn't say insurance will cover the cost.