Lips Study - Digital Drawing

Here is my new digital drawing.
For today's drawing, I tried delving into something different - a study of the human mouth; with the focus on her lips. It looks tempting as it seems to be biting a section of the lower lips.

With my favorite style, I used scribbles to build my first coat with some other lines that flow according to the shape of her lips; that was followed by smudging which added more forms.

The sketch was done with AutoDesk sketchbook application and aided with an S-pen. My steps can be seen below:

Thank you.