My BP (Delilah) has a spot like that on her side, from when she tangled herself up in a light wire... it was secured to the cage, but she somehow managed to break it loose. Dumb - or smart? - snake!I had to help her get free, and she scraped a few scales in the process. So maybe it was something similar? I'll see if I can find a picture where it's visible, and you can compare if it looks like yours.