Like Arctic, I would recommend reinstalling your game completely. With
the black heads, it seems that a shade/texture file has been deleted or probably corrupted, and
now your other more essential FeralHeart files could be doing the same. This can
happen over time, messing with things on accident, or adding in a separate faulty file that comes
with a mod download. Anti-virus softwares can do it too, just like Hakumi said, so digging
into that may be a good plan as well before reinstalling. Some antiviruses will delete anything
that so much poses the tiniest risk of a threat, even if the files are completely harmless, like
FeralHeart's are.
But, however, removing everything and reinstalling is probably your safest and best bet.