Hey Bella!
Wow! this piece is very nicely toned, You've done a great job at taking some solid advice in this post and applying it to your drawing. Your original and drawing look the same age and have a very nice feel. I like it!! Let's talk hairline, Adding Whispy's, (as I call them) Is key to not getting the "holy crap I'm wearing a wig!" Look! The human hairline usually doesn't come to a dead stop, it feathers away, especially along the side's just above the ear. there are also loose hair that hangs along the top. These "Whispy's" have to be drawn in to get that realistic natural look. Everybody's got them!!!
Matti and Bill are really good at this so, chime in boy's!!!
I usually use an F pencil with a very light touch and draw them in.
I then use a very sharp and clean tortillion to soften them, push them out of focus. They can't be harsh!!! They have to be seen, not heard!
The best thing to do is make your husband sit and examine his hairline, see how the little guy's creap in and feather away. he may think your losing it but hey! It's all in the name of art! Do it during the superbowl He'll never know your there! (GO RAIDERS!!!)
Give it a shot and post a nice close-up so we can have a look-see!!
Peace!!
Marc Forest.
http://www.marcforest.com