to change the 'mood' icon, click on the one under your name, on the upper right, and a little drop-down menu should appear,,, click on the one you want, and refresh your page.

(yes, many of us do return to see what people have said to our posts )
if you feel you have something personal to share or want to be sure the person sees it, if they are new and don't know that all their posts can be found under "Statistics", you can click on their name in the upper left of the post, and send them a PM (or a nice Public Profile message).

best wishes~