This seems to be an old thread. I don't know if my experience is quite the same but I figured I would join the conversation. My symptoms only started recently. I have heart issues, and wonder if it could be the medications. When I start sweating, it feels like fiberglass. It also happens when I am not working out. I lie in bed and start feeling it, just not as pronounced. It is usually on my face, but occasionally can be elsewhere. My wife has recently put me on milk thistle and I wonder if that could be what is causing it.