Course there are a couple of tricks you could try first:
Try and suck it back out yourself using an empty toilet paper roll.
Try and carefully suck it back out using a vacuum.
Try and pull it back out using a piece of tape.
You do risk more damage to the driver with these options but many people have had success.
You'll likely be able to purchase a used one but they are a bit on the expensive side when you can find them.
You could also just leave it alone, but the grill back on and not worry about it :yikes:
in another forum it is said, I have to dismount the tweeters dome reform it and mount the system again.
Is it possible with this KEF?
(With Visatons it is easy everyone can buy the domes as a spare part to chnge them.)