any help will cause eternal apriciation <3 (issue about body meshes or default skins??)

[cisupark]

i use dumbaby's big bottom and bunch of diffent skins, anybody can tell me which package causes this blackish line and lower res bottom, i remember my sims asses were clean and hd since this black line settled lower end of the butt it causes major uncomfort for me... pls help, which package to delete, or add for get rid of this??

thanks in advance...