One of my tester’s for this (zodwollop) put eyes and ears on her hippo and was kind enough to tell me how:

I used tiny onyx beads. Any round black beads would work. I colored around the edges with a little bit of colored pencil.

You could also do french knots I think.

I did two stitches for each nostril (I just went from top to bottom over the nose) and shaded a little at the edges with pencil.

You could do the face without pencil and it would be fine too.

Her ears were just a magic ring with 3 sc. I knotted the two tails together and sewed them to her head.

Thank you!