FD,
You do not say, but is this limited to just the one hand, or does the neuropathy affect the whole body?
Discontinuing the Omega-3, if that was the cause of your symptoms, it would affect the whole body, not just one part. Where as, the chemical compound could cause both a local neuropathy and a systemic one.
Hopefully, the electrical studies will elucidate the cause of your problem. Though the cause of a neuropathy can usually be determined, occasionally, no reason is ever found. In those cases, the neuropathy is treated symptomatically.
Good luck.