Yeah, it's his eyebrows and his mouth as well. Squirrel villagers typically don't have big mouths. But don't let this stop you from drawing! You can really improve if you keep trying and point out your mistakes. I can tell you that I've learned that through approximately three years of drawing.
If there is something you can improve on, it's your colouring. Try colouring only in one direction and not in many ways. I can see that you took many different directions and if you only took one and stuck with it, it would look MUCH better.
The positives from this are that you tried your best to attempt this and Static's big smile. It's also worth mentioning that you got his eyes right at least!
But if you really like to draw big eyebrows, you should try Hazel. XD