Hi!
Looks like your little one could be about to shed. His top and bottom layer of scutes will start coming off slowly. (Dont try to pull them off....its tempting, but it can do it itself

) Also, RES shed skin also, all over. It freaked me out at 1st also, but it is normal. It looks like whispy clearish stuff in the water and hanging off the turts head, neck, legs... If its water temp is too high (over 82ish) it could cause a little excess skin shedding.
He looks just like my baby. (not the one in the pic.. she is my BIG girl, lol, I have a new teeny baby also.) Very beautiful! My baby's plastron (shell) looks almost identical to yours. With the gray areas between the scutes on top and all. Soooo cute. Mine's about ready to shed his scutes also.
To me, the shell looks healthy. Im sure others with more knowledge will comment soon!!!
Welcome to the Board!