

Stain on silk blazer
Hi everyone,
I have a cream/off-white 100% silk blazer (luxury tailored jacket) with a visible tone on tone stain on the lapel area.
The strange part is:
I have no idea what caused it. It’s not visible at all lighting but I can clearly see it.
It seems deep in the fibers rather than surface dirt
I already took it to a professional dry cleaner and they told me they tried everything and there’s nothing more they can do
The fabric is pure silk, so I’m scared of damaging it. What should I do?