Well usually when I hear of the burning and sometimes itchyness, I think of hubby and his PN. He developed that after almost 7 years on statins, then became diabetic, so they blame it on that. Only thing is, he had the PN before being diagnosed with diabetes, so to me the combo is what messed him up. Like you, there is no visable signs of a rash, just burning and now numbness and he thumps his legs half the nite on the mattress trying to get to sleep till the pain pills kick in. Last year it is going into his hands, so he drops alot of things, especially little things like screws etc. when trying to work on things, as he can't feel anything, yet he feels pain.
Hopefully you get some kind of answer, as it most definitely could be the Rice stuff,as you said, it is a natural statin. Keep us posted and good luck..