Are you looking for the hair? Several modders may have contributed to this Sim. The lips look like Obscura's lip slider mod (
https://obscurus-sims.tumblr.com/). The ear-fin things looks like Zaneida's work (
https://zaneida-and-sims4.tumblr.com/). The skin and eyes could be from different creators too?
The hair looks like a Stealthic creation (
https://www.simscc.com/?s=persephone) All the retextures I found still shows the one-shoulder look of the original. Can't find one over both shoulders.
Do you still have the link where you found this pic? Might be a clue there?