When I initially got sick my tongue was black.
kinda purplish real horror movie stuff
turned out it was hairy tongue which can be caused by the body fighting illness.\
I had to use bleach and a toothbrush to get rid of had to be careful of course not to swallow it
took a lot of scrubiing and oh was it sore but I got rid of it.
I don't know if u have hairy tongue but I thought I'd throw it out. Sometimes candidiasis can cause discolartion but I don't think it makes the tongue look as black as hairy tongue.