Step 10: Lightly sketch the eyes inside the head as two small circles. Use the initial lines as guides for the placement and size of the xoloitzcuintle's eyes. When you get the circles right, darken them. Draw a couple of angled lines on the sides for the corners of the eyes. The eye on the right should be slightly bigger because of the way the head is turned. Darken the circle on the right and draw the pointy corners of the eyes too. The inner corners of the eyes should point downward a bit toward the dog's muzzle.
Step 11: Draw a few curved lines around the eyes for the eyelids and skin creases. Xolos are mainly a hairless breed of dog, so their wrinkles are more visible, especially around the eyes. Inside each eye, off to the side, draw a tiny circle for a highlight. In the middle of each eye, draw a dark dot for the pupils. Shade the xoloitzcuintle's eyes using a light value. Make the top parts of the eyes slightly darker for a rounder look. As you shade the eyes, don't overlap the tiny highlight circles.
Step 12: Inside the muzzle, near the right side, lightly sketch a small oval as a guide for the nose. When you get the position and size of the oval right, darken the top edge. Darken the right side but curve the line inward to create the first nostril. Darken the bottom edge of the nose and add a small line at the bottom. Darken the left side and curve the line inward for the other nostril. Draw a pointy, triangular shape at the bottom of the nose for the bit that will connect to the mouth. Shade the inside of the dog's nostrils using a dark value.
Step 13: Below the nose, draw a line that curves to the right for the first half of the xolo's mouth. Use the bottom edge of the initial circle as a guide. Dip the line down for the droopy lip. Stretch the line outside of the small circle. Draw a smaller line on the left for the other side of the dog's mouth. Curve the line up toward the nose to finish the front part of the muzzle.
Step 14: Draw a short line under the dog's mouth for the visible part of the lower jaw. Draw a couple of sloping lines from the top of the nose to the eye on the left for the top of the xoloitzcuintle's muzzle. On the front part of the muzzle, below the nose, draw a few dots and broken lines for the base of the dog's whiskers.