'your hair!!!' or 'look at your hair!'
I've not cut it in a while so it's longish. However, hair growing is a pretty gradual thing when all's said and done so it can hardly be called a drastic or sudden change. Seems I've reached a tipping point recently where people are suddenly noticing the length. They're not offering a compliment or anything, just a comment.
What do you say in response? I keep feeling all awkward about it so just trying to think of some lines in preparation.