Wow, I never seen that depth of damage before. It appears damaged by a fire.
If it is in-fact only paint failure, then having the entire B+ cap stripped & repainted seems a logical choice. If the damage is limited to a very small area and you don't want to spend a lot of money, you could get creative, create a pattern, paint that section using the pattern as a template, flip the template, and repeat on the opposing side for intentional balance.