Rubbing alcohol evaporates at room temperature. If you let it sit out so it all evaporates, you'll be fine.

Besides, what the fuck do you think they use to make hash? They use rubbing alcohol or butane because THC dissolves in them. Last time I checked, lighter fluids weren't the safest things to be putting in your body. They let the butane or alcohol evaporate and it's all good. Besides, if there was still 99% isopropyl alcohol in with the weed, your weed would probably burn like gasoline. Alcohol is extremely flammable.