At least take the cover off for awhile and let the vermiculite dry out a bit. Be sure to do the squeeze some between the fingers test and make sure you aren't squeezing out water. You should feel some dampness.
The only vermiculite I could find was the fine stuff...I'm using it but don't like it. I monitor the eggs once a week and make sure the temps stay fairly cool.
Good luck. Hopefully you can save some.