Damn man, it sounds like you did dry them for too long...that sucks.
What you can do now is either leave the buds to be dry and easily crumble-able in order to roll easier J's.
Though, if you don't want to do that, there are a few things you can try.
Here are some of the best tips that I found on the net:
1. Get a cotton ball, wet it, place it in tin foil, poke holes in tin foil. Let it sit in jar with bud, for couple hours, should return moisture to your buds.
2. I've seen some growers stick a wet paper towel to the edge the container and seal with success.
~~~~~~ORGANIC METHODS~~~~~~~
3. Another trick is to put your buds in a jar along with a few fresh orange peels. Shake the jar or rearrange the nugs and peels every four hours so to ensure better moisture distribution. Be careful how many orange peels you use because you can easily over moisturize your nugs. Have used it many times before with crumbly bud. Also, it adds a nice citrus flavor/smell to your buds which may not work well with all strains.
4. Skin just the other layer of a lemon peel and stick it the jar overnight. A couple of strips will do. Remove the peels in the morning to prevent mold. You should be good after that. Just keep burping the jars a regular intervals and the faint smell of lemon should dissipate as well if you burp enough.
5. I have always just taken a fresh small bud plucked from a plant (of course it matters to have such) and throw it in with the too dried, and seems to have worked well in the past. And you can monitor it and take it out once the desired moisture has been achieved, or even add another if that one dried out.
6. Putting the dry buds in a bag with a slice of fresh bread and leave it overnight. Brings back just the right amount of moist back to your buds when too dry. Potato peels work fine as well but both can leave a smell and a taste that may be undesirable
7. Lettuce (fresh) is the best for least flavor transfer. About 3 hours in the jar would do it. But you should check it yourself
8. A piece of apple would probably serve best. It does not contain the aromatic oils of the citrus fruit and none of the yeast which could also cause mold, like in the bread.