Yes, these look like Euonymus Leaf Notcher caterpillars, but the Camellia should be safe, as they only eat Euonymus (and its weedy relative Bittersweet vine). We think there is only one generation per year (so will soon be gone in that case), but it's still a comparatively new insect for our area regarding info. about exact life cycle timing. While organic pesticides like Bt can kill young caterpillars while sparing most other insects, these appear to be too old to be affected by a spray at this point. Once they are gone, the plant should recover fully, as Euonymus tend to be very forgiving and vigorous plants. (If it doesn't, some other stress factor was contributing to the plant's decline.)

Miri