Splitting maybe?

I forget what this is called, but it looks like it is splitting in half. Down the center of the trunk is indented. I had a powerhead fall at the beginning of the week and really pelted this thing with sand. Was laying sideways and the half that was touching the sand looked dull and lost a lot of it's green color. The half on top lost a little color, but not much. I've just been watching it to see what it would do and every day it has looked a little better. Today is the first day I have really noticed the side leaning toward the sand getting it's green back and the indent is new today.Is this possible? I attached a pic of it before the sand beating also.

colt coral. wish mine would grow like that.

I wouldn't worry about it. They are tough corals and reproduce by splitting, dropping arms and budding off.