Instead of cutting out the face, I tried painting the 2 halves, shading for a bit of dimension. The background is pastel in the complementary color to the blue in the face. The pastels could be left like this, or smoothed over with a bit of paper towel for a blended look.
All the details were drawn on a separate piece of paper and colored with marker or crayon.
I like the idea of backing the whole piece in a color to complement the colors used in the collage/drawing.
The whole purpose of this exercise was to play around with breaking apart faces/profiles and gaining some understanding of what Picasso was experimenting with. I guess you can see that the possibilities are unlimited. I hope some of you give it a try with your students trying some other options!!