Every year, my Camellia sasanquas get leaf gall.
This disease is caused by a fungus, Exobasidium camelliae. Infected leaves become fleshy, thick, and discolored.
While disgusting to look at, the misshapen leaves don’t do any serious harm. The disease may be controlled by removing the infected pieces and disposing of them in the trash (not the compost). It’s best to do this as soon as you spot them, before the galls have a chance to fully develop and release their spores.
Moist and humid weather produces favorable conditions for camellia leaf gall to develop. We have certainly met those criteria this spring. I have never seen the disease on my japonicas (the spring bloomers); only on the sasanquas (fall bloomers). Take a look at your camellias and if you spot the problem, don’t reach for a spray. Just nip off the swollen leaves, clean up any that have dropped, and your plants will be happy again.
MissingHenryMitchell 
A lovely camellia that my husband bought is struggling to survive leaf gall. I tried everything that the county extension office master gardener recommended: removing and disposing of the leaves, pruning the bush to give it a more open branching for the air to circulate better (although there was not much left to prune) and move it to a sunnier location that has better air circulation (it was next to another bush). Several years later and it still has only a few cluster of leaves, but this year it had no evidence of leaf gall even though it has been an extremely wet summer. I still have hope of it recovering.
I hope it recovers, too! It is encouraging to hear that it isn’t showing any signs of leaf gall this year. Stay vigilant, and please let me know what happens.