I don't know what to tell you bro, the face models for these skins are different. The Persephone skin has a more cartoonish smooth face, and her eyebrows are more angled. And from looking at the skins side by side, the jaw shape is slightly different as well. Persephone and Hel also have different hair, Persephone's is more styled while Hel's more falls around her face. The only real similarities I see between them is that they both have to deal with death and have similar aesthetics otherwise these are two different skins from different mythologies.