Happy day, I got the prop out and the mold cleaned up ok. The prop is rubber but I can let it sit forever and see what happens. At least it showed me I got the right amount of CF tow in the right places, that hardly ever happens on the first try. Next prop will be rock hard.
If this is a matter of time-related changes to the material in an industrial-quality epoxy (which I certainly hope you are using, instead of a filler-laden consumer type), I would either contact the manufacturer about what to do, or replace it with fresh. TDM may well be right about heating it up and making it clear again, but I would bet you could find that heating it up to any degree exceeds the storage environmental requirements. Most modeling applications, if it looks OK and feels OK, it's probably good enough, but not for something where you have a critical safety issue like a prop.
I also don't want to assume you *don't* already know this, but you need to follow basic engineering recommendations for composite construction of high-stress parts, and make sure you weigh out the resin and the carbon to ensure you have the right ratio of solid to matrix for the proper strength. In most places in modeling applications, you can afford to eyeball it because it's overkill anyway, but the margins around the hub of the prop are not good and fatigue is a real factor.
Brett