Is there a way to get makeup colors to look the same, rendered, as they do pre-rendering?

I've got a character wearing red lipstick, but the lipstick looks more pinkish after rendering.

you could try altering the lip difuse color to a red to enhance the red of the lipstick....

If red is turning pink I suspect it's die to the specular highlights washing the colour out - try raising Glossiness, for a sharper, smaller highlight, or lowering Specular strength (in the Surfaces palette).