So, you want to shade, but some features are blurry and unrefined??

I got you.

 

 

Here, in this screenshot, you can see the nose is blurry and not well refined, right?

 

 

To fix this, I just go in with my Gpen and select the color beside the nose

Now, with the light color, I go in and crisp up the line.

After I get the nose refined, I go back in with my blur tool, to soften some edges.

Here’s the before and after

I hoped this helped!