Khardic Flesh vs Lipstick

How close are they?

ΔE 38.7, loose: different enough that you should pick on purpose. Lipstick is a little darker, much more saturated, cooler than Khardic Flesh.

Can I use Lipstick instead of Khardic Flesh?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 39). Lipstick is a little darker, much more saturated, cooler than Khardic Flesh.

Can I use Khardic Flesh instead of Lipstick?

The same difference applies the other way round: Khardic Flesh is a little lighter, much more muted, 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.