Is that actually hoof wall? It's hard to tell, but it might just be periople that's dry and shedding a bit. Periople is like the cuticles on our fingernails. Sometimes they can look a little ragged on horses, especially when they extend down the hoof a ways. But it's totally normal if that's all it is. You might need to take a wet brush and scrub that part clean and take another pic.
As Steady said, it may just be periople. If it's actually lumps of hoof wall, there's been some (minor, I think) 'insult' or stress to the coronary border a few weeks or more ago. Because they look like uniform distance apart, makes me wonder if he might have kicked some barbed wire or some such.