I know what this is. One of my females had the exact same thing a while ago. Took me a while to figure it out but I caught her in the act. My snake tried to stick het head between the lip of the bin and the shelf above. When she pulled her head back in it ripped some scales off. The 2 marks are where the jaw bones are, thus those spots press harder on the bin below and when they move their head back the scales get pulled off. My lady healed up fine. Just keep it clean. In a few sheds she will scar up. I'll post a pic of my girls chin now so you can see. I'll also see if I can dig up the thread I made to show you the pics of her jaw when it happened. Keep it clean and your snake will be all good.