When Minna 'painted' semi-realistic portraits of the crew, we all went off our nut admiring Emil's kissable lips. The rest of the crew still ended up with thinnish lips in that series.
Yes I remember this series (especially Emil's, got me swooning when I first saw it). The lips were still very subtly drawn, but when I saw them I was like "wait. something's wrong.". Then I realised the characters in the comic never had lips, which I had never noticed before. ^^"
For Emil and his mouth, maybe try to make the teeth in an arc rather than a straight line?
Now that you mention it, you're right! I should draw them in more of an arc.
Teeth are hard too, if I draw them too realistically, they make the character look terrifying, and if I draw them too simplistically, then they look wrong too.
May I start a petition to remove all teeth in art so I don't have to draw them ever again??