Those spots on Happy’s back could be many things. If they are raised, more like a tumor, then I would recommend to have him seen by the veterinarian who may collect a small sample of cells to know if it is concerning or not. If they are flat, then you may monitor them at this time to see if they go away on their own. Dogs can get superficial bacterial infections, small wounds, ringworm (which humans can get as well) and other minor ailments that will often heal by themselves. If the spots do not go away within two weeks or if they get worse, then plan on having him seen by the veterinarian. I hope you find this helpful and please feel free to post any additional questions.