I tried to change my thermostat for my Carrier 38YRA WeatherMaker Heat Pump, and the replacement thermostat didn't have enough wires, when I put the old one back on, it was blank.

The R and C wires are hooked up. Is there a fuse I need to check?

If you didn`t turn off breaker to furnace before installing you might have blown the low voltage fues in the circuit board,, or maybe fried the transformer, you didn`t say what kind of furnace you have
Electric furnaces (most) don`t have a low voltage fuse

Its an electric furnace. Breaker is not tripped

OK,, but you are supposed to trip breaker off, before installing a new tstat,, then turn back on.. the least little spark,that you can`t even sometimes will fry the transformer and has to be replaced

Just hope it didn`t happen to you