I feel like the lips are too light

This is a good start, try to follow these steps and finish your work: 1. Carefully examine the references. The value of the fabric, lips, and eye whites is not the same. Often compare the tones of different elements and ask yourself questions about what is brighter and what is darker. Also, try not to use white color to lighten painting. 2. Find a simplified model of face lighting reference that closely matches the photo. Try to apply this lighting scheme to your work.