Day 3:
I found myself mostly using 4H, HB2 and 6B.
I use 4H to draw the base lines of the lips and add some minor details in the lips before moving to 6B to add some nice dark lines on the middle of the lips and began to shade from dark to light. I will add more details on the lips with HB2.
So here is the lips I managed to draw up on my third day: