CIDP and Lithium

Before I was diagnosed my doctor was not certain if the drug , Lithium...may have caused the CIDP...in other words Lithium induced CIDP. I was taken off the lithium but symptoms did not improve. Any one else been in this situation? The nerve conduction tests i have had show my condition getting worse. I question whether or not I really have CIDP. I was on lithium for over 4 years, and now off of it now going on two years. So maybe the damage has been done and there is nothing that can be done to reverse it or stop it from progressing.Any input would be helpful. Thank you