The only suggestion I can make is to add some fine creases and lines to the eye pouches themselves and below the lower eye pouches. Don't know if that would help or not. The likeness is so good right now, I'd be tempted to leave it as is.
Are you planning to thin the edges of the shirt collars? Would look better a bit thinner.
Thanks for letting me make suggestions! Hope I helped a little.
All the best,
Dan