Very interesting lawstudent.
I have never taken selenium by itself but I get it various supplements, can't say exactly how much I am getting but I too have noticed the bruising thing, slightest bump turns into a nasty yellow bruise and tiniest cuts or scrapes turn into these big scars bigger than the original cut and takes forever to heal and never is the same.
Vit E, fish oils, vit c are said to help but has not helped me.
But I have never had the geographic tongue. I have thyroid conversion issues that have also not be resolved yet and may not get resolved until the mercury is out.
Get better

Veg