If you are overly concernedabout it you could even post up a few new photos of you with hair and a hat placed on top or joking about with a hat on that way people will see the new hair underneath the hat, or even a beanie/sweatband or something showing you have hair.

Then take it from there.

Could even go for a transition of photos. Go to a function where you are well dressed e.g like you are dressed for a wedding, conference or something with a smart shirt and slacks. That way you wouldn't probably wear a hat.