Flayed One Flesh vs Pale Skin

How close are they?

ΔE 17.4, loose: different enough that you should pick on purpose. Pale Skin is noticeably lighter, more muted, cooler than Flayed One Flesh.

Can I use Pale Skin instead of Flayed One Flesh?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Pale Skin is noticeably lighter, more muted, cooler than Flayed One Flesh.

Can I use Flayed One Flesh instead of Pale Skin?

The same difference applies the other way round: Flayed One Flesh is noticeably darker, more saturated, warmer.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.