@BlackAzizAnansi NK Jemison’s Broken Earth Trilogy isn’t classed as horror, but has body horror within it IMO, and definitely ticks the dystopia box.
https://www.goodreads.com/series/112296-the-broken-earth

Jeff Vandermeer’s Area X series I would call horror/dystopian.
https://www.jeffvandermeer.com/book/area-x

I’ll try to think of more, but I don’t tend to seek horror in my reading. 🤷🏻‍♀️