I remember there was a study a few years back that showed that up to half of people with fibromyalgia can have levels of nerve damage. I've also personally met people that had horrific car accidents being the primary incident which led to their fibromyalgia onset. In part, nerve damage was consistent with their symptoms which could also have the appearance of Bell's Palsy like symptoms.
I tried doing some research and from what I read, it seems like Bell Palsy like symptoms can be mistaken for fibromyalgia, or vice versa.
As for a direct link between the two, or having both issues, there doesn't seem to be much literature on the topic. It's not impossible to find articles that mention both afflictions in the same article, but they seem to be few and far between.