We don't know, I mean 2d is far different from 3d, they prob just make her look like that as to be more visual friendly to audiences rather than drawing an actual "ugly beast" look, setting off its description instead, as the indigenous people there sees her as such, then she probably do look like that, it's just that her face is seen in a lighter or censored version by us as not to create any aversion to the readers, or the artist couldn't just properly portray the "ugly beast" look.

Someone tell me how kawana nanako’s current appearance is “ugly”? And to the extend that she’s called an ugly beast lmao?? She just has freckles now. In fact if anything I feel like she looks better / more natural compared to her “pretty” look, that was just too fake and plastic.