The browning of the uppermost flowers is likely to be sun damage - although Camellia japonica will grow and bloom for decades in full sun (regional climate permitting) much of the time it would still look better in partial shade even in those locations where it can survive significant sun exposure.

The marbling of the leaves may be a virus. In which case there is nothing to be done about it.

Thank you! It is in a very sunny area, so direct sunlight makes sense as the cause of the browning. Hopefully the discoloration is nothing too serious.

My camellia flowers look like that as they age whether they are in sun or shade. I don't know about the leaves. I get a few like that but never that many.