I was told by my breeder that these bumbs are simply puppy acne. They are caused from their food and water dish material. The best thing you can do for them is to get stainless steal bowls for them and give it time. They will grow out of it and I wouldn't be worried unless they seem to irritate him.
It could be just an allergic reaction to something outside if its really bugging your dog you should prob take it to the vet
Sometime it's the place where the whiskers come out of his muzzle and it's natural. If they're red, sore, or pus-filled, take to vet