That appears to be a small chunk missing.
Short of replacing the case, professional repair, or sanding it down (which will be very apparent because it will remove the anodized coating, resulting in multiple colors, and you might have to sand it so much it will alter the angle of that edge), you could try finding an epoxy putty in a matching color to the casing and building up small layers using a toothpick to apply until it fills in the area, and then carefully sand down the edges of the dried epoxy to make it match the dimensions of the case. You would probably need to prep the area to ensure good long-term bonding, and want to tape off the non-damaged areas to avoid damaging them more. The end result will still be visible, but less noticeable, and you would no longer have a sharp edge.
You may want to take something else that is aluminum, intentionally ding one of the edges, and practice this method a few times to ensure you can properly prep the surface without causing more damage, apply in the right amount, sand without causing more damage, and are ultimately happy enough with the outcome to then do it on the MBP. In fact, I highly recommend practicing this before trying it, so you know what you are getting yourself into, understand the technique needed to do it properly, and are able to see the end results (and how colors of epoxy can change some upon curing) before you fully commit to this on your expensive computer.