Maybe someone will come along with a better answer, but I only stopped having this problem when I stopped doing creases all at once. I gently shade them from the beginning and blend them out. Let them disappear. On some kits they do 3 or 4 times just like the vinyl eats the warming washes we apply, but eventually it will show up, and when it does it won’t look dirty.
The color is a tough one because the color depends on the color of my doll. Mine is usually a few shades darker than the doll and includes a blush shade.
Sometimes I also use powders.