There isn't a standard test for chemical exposure .But I would venture to say that in your line of work you had some pretty significant exposure .
Have you had any liver enzyme tests ? This isn't a definitive test but it could help point you in the right direction .
If you use milk thistle and NAC and MSM with vitamin C it will help clean out your liver .Sometimes I think that some of us are suffering from from pollutants and then we get exposed to a parasite and we treat the parasite with meds and we are overtaxing an already over taxed liver .So its a catch 22 .Or perhaps some of us dont even have parasites its all due to a toxic body .
I think the best thing to do is to try to clean and detox the body as a first line of defense then reevaluate and then use the meds if necesarry .
The more I think about your situation the more I realize I have had that crusty stuff and flaking on the eyebrows and hair .It was a long time ago and I was drinking a lot at the time and not taking proper care of myself.I really wonder if your liver isn't toxic .
I havent seen you on here for awhile and I am just hoping that you are okay and small axe didnt scare you off !!!