Watermarks on silk clothing

[Mamapep]

Husband spilt black coffee over a vintage silk gown whilst carrying it to the car, I panicked and threw it in a cold bath. The coffee didn’t stain it thank god but after it dried there were big watermarks round the hem (heavy embroidery/embellishment on the hem so your eye is really drawn to it too 😞)
It’s pure silk, quite fine like a fine silk chiffon weight. It was very heavy after soaking and i dried it hanging up.

Is there anything I can do for the watermarks? Will handwashing help? There’s no care instructions label in it.

If anyone has any tips/advice I would be very grateful, I would love to rescue it.

Eek

When I get water on silk, I blot it and then dry with a cool hairdryer from the outside in, which prevents the watermark.

For the whole dress?
You could try wetting it (I'd spray until damp rather than soak) and then try this technique. Advantage to spray means you could do a bit at the time.

Thank you, will try that!