Perhaps camellia scale?

See if the link below helps you. It contains some pictures of leaf damage caused by pests and fungal diseases. You may be able to confirm scale by comparing.

Scale is one of the most severe insect problems associated with camellias. Their hard outer covering/shell protects them from contact insecticides and makes them difficult, but not impossible, to control.

Oil emulsion sprays, applied early in the morning and on days when temps are 85 degrees or less, will give effective control but must be applied a.s.a.p.. Spraying in the afternoons or on hot days can burn the leaves. Re-apply 60 days after the original application but no more than 3 times a year.

Good luck, aggierose!

Here is a link that might be useful: Camellia Leaf Damage