Jeyes Fluid for Removing Moss on Car Stained the Paint?

I have a car which has not been used much. Moss had grown on the window rubbers behind brightwork and on the inside of the door sills. Yesterday, I used Jeyes Fluid to kill the growth and to lift the growth with a soft brush or cloth. I washed the car down well afterwards.

Now the exposed paint is stained brown, but the sills are perfect! How come different parts of the same car are responding differently and how can I cut deep enough to remove the staining. TCut on a slowly rotating mop (speed setting 2) has had minimal effect so far. The car - is a DS3, white with black roof, etc.

Thank you for any suggestions short of a respray!