Arijana is right, it’s very likely a reaction to the biotin showing up as die-off symptoms. And your description sounds too much like die-off not to suspect it, Day, especially considering the biotin.
There’s a post about biotin’s potency for treating the infestation.
Raster/Able, if you’re reading this, how do you feel about soybean oil? Should it be avoided?
Soy oil should be avoided in larger amounts, but it’s sometimes impossible to avoid in supplements. In this case I doubt there’s enough to make much of a difference – unless you’re allergic.