Betta Fish: What’s up with pixie, help please

Just wondering why he looks worse for wear, colour slightly faded (the first picture is him last month) he was fine last week aswell, I posted because he has a white spot on back but that’s seemed to have gone. But now he looks slightly see through, and his face looks abit battered sorry for the bad pictures it’s feeding time so he won’t sit still haha. Just worried because he’s my world.