Hmmm...
Still not sure of location, but if the pic is the case neck mouth location in your chamber, it receives the full brunt of the flames exiting the case mouth. That fire cracking / checkered appearance looks about normal, and is caused by the flame temperature and erosion from gun powder and hot gases exiting the cartridge case on the barrel steel. Nothing can be done to avoid that. Each shot fired takes its toll on the barrel.
I say keep on shooting it, as if you never saw your photo. Provided it shoots good.