Hey man, if you've still got some sweet smellin bud left, put it into a brown jar with your "Hayweed". It won't bring it all the way back, but you'll regain some of the smell. It may even help lessen the harshness that "hayweed" gets. Except for rare circumstances, the THC isn't affected very much by the reduction of flavors.
You might also try peeling an apple or two and puting the peels into the bag to rehydrate the weed a little. It helps the hayweed taste too.