A Google search of "Plexus for pain" brought up Plexus Fast Relief capsules which contain green lipped mussel powder, tumeric and other ingredients that have anti-inflammatory properties. I am not familiar with it.

As far as supplements I have only tried the few that have at least a little research based evidence behind them for helping CRPS or inflammation. NAC - n-acetyl cysteine is one recommended in early cold CRPS. (Mine was hot, so never tried this) I did take Vit C for a while and still do before and after any "trauma" or procedure. I also have used PEA Pure (palmitoylethanolamide) which is a fatty acid approved in Germany and Italy for neuropathic pain. I took it for months and still keep it around in case of emergency. It reportedly downregulates microglia and its developer Rita Montalcini won the Nobel prize for discovering nerve growth factor during WWII. I ordered it from overseas but see that it is now also made by a US company.