Those spots on Tank could be several things including allergies, skin mites, flea bites, ringworm (which humans can get), endocrine disease or a bacterial infection. You can try adding in an omega 3 fatty acid supplement for dogs, this can help improve the skin health. You may also try changing his diet to something like Royal Canin or Nutro as they are aimed at skin health. You can wash the lesions with a medicated dog shampoo every other day and rinse well. Protect the areas from licking or scratching. If they don't start looking better within about a week or if they get worse, have him examined by his veterinarian who may prescribe medications or diagnostics. Best of luck and please feel free to post any additional questions.