The white spots could be a leaf disease or an insect such as scale or mealybugs. I suggest you take some leaves to your County Extension Office for them to look over and diagnose/identify. Their contact info is:
43 Maple Street
Ringgold, GA 30736-2313
In the meantime try fertilizing the plants with a product for acid loving plants such as Azalea/Camellia food or Miracid following label rates. Camellias need a bright area but not direct sun for best growth and blooming.
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