First how did that happen?
If the card works you should be fine. It's really not worth getting fixed.
That is part of the PCB, so they would have to replace everything but the cooler.
The x16 sockets are pretty deep, so I assume it is still making contact.
There is not real DIY to fix it because you will end up shorting out some of the lanes.
There may have just been a copper coating on the PCB traces connectors and have worn off.
If the card still work you should be fine.