Warning, contains wound pics!
Ollie caught his back on something, it was healing nicely. Then he pulled the scab off. He's just done exactly the same thing again and I think it's when he is nosying about outside and catching it on a hedge maybe
I can't keep him in - this cat has an inability to be quiet and will keep up the song of his people for hours on end to the point you need subtitles on the TV...
If he was human I would have put a padded dressing on it but.. cat 
It's clean, and it heals but he just keeps ripping the damn scab off
Pic this morning and now