This is such a great work. The softness and the resemblance to the original it's just stunning, and definitely one of your most realistic drawings ever. The only two things i see a little bit off place are the lips, which (i think) they should be a BIT less lighter and the neck seems too bent. In spite of those details, it's a TOTAL genius work of art. Congratulations, you've improve your technique with women faces a lot, and this definitely proves it.
PD: the lips (even with those minims flaws) are way more better than previous works. Good job!