Sometimes files get corrupted, but when that has happened to me, it's usually horizontal lines of different colors. Yours looks a bit mottled.
I'm surprised that even with part of it being corrupt that the file still opens. Photoshop usually corrupts my files after I download an update, which I had done an update that day.
There are lots of JPG repair apps on the Net. Some of them are even free.
Here's a wee tale of woe:
My wife's computer was getting sicker and sicker so we decided to do a clean reinstal of Windows 7. I copied all the data off it, and replaced it after reinstalling Win 7 - except it wasn't all there. My wife is mad keen on family history, and had stacks of irriplaceable data. It would not have gone down well if I'd lost it for her. The files definitely weren't on the USB3 pocket drive I'd used, and things were looking desperate. Then I remembered that I'd done another full back up of her system a month ago, and all the data was safe.
I've lost two drives in recent years, and both times was oh so thankful that I had proper backups.