Replacement for Edifier s350db Titanium Tweeter?

Did you remove the tweeter and look at the back to get some information?  The name brand should be on the back of it. If it is a well known brand, Madisound may sell it or  have a replacement for it. 

If it was me I would contact Bill at Millersound and ask if he can fix it.  I have great faith in them.

Try sucking it out with an auto body dent puller from Home Depot

TAPE or a dab of super sticky something on the end wooden cooking skewer (flat end) DAB the dent and pull it out, If it's cracked, yikes..
very thin coats a bit at a time of silicone or something to stop the rattle..

You can let a dab of silicone dry a bit and pull the dent that way, then razor blade the dab off, be careful.. Few ways..

Vacuum cleaner with a hole in the hose, so you can release the suction or increase it if you need to..

Regards

You may be able to disassemble the tweet and push the dome from behind.