Noticeable neck seams?

I've been having this issue for months, and I can not find a way to fix it. I've attached photos of what's going on. These are from a fresh reinstall of the game, no mods or CC. My game is on highest settings.
There's also a weird little white mark on the seam.






It gets even more noticable when I add in my normal default skin replacement (KURASOBERIN Primer)



Is there something going on with my graphics card settings that would cause this? Please tell me someone has the answer, as it's really frustrating me!