How do I save curry with too much cumin?
If you have a dry seasoning taste it's possible that the spice simply wan't cooked enough. If you added a load of cumin (or other dry spice ) at the very end then it may not have had enough exposure to heat. If this is the case then simply cooking it for 10-15 minutes may improve it somewhat. 

One thing that has worked for me before in similar cases is adding some yogurt or a dab of cream and cooking it for a bit. I think it may be that the fats in them help the cumin to release their essential oils, or it could be that the flavors of the milk have some sort of interaction. The reason it has worked is unknown to me. 

Beyond that there's nothing you can do that I know of. A bit of cooking work yogurt is probably worth your time and effort to save it, but any more than that is likely a waste of your time and money.