When the wire shorted to ground it put too much of a load on the O2 Sensor's heater supply wire. The PCM most likely detected that it was shorted and internally shut reference power off. It's a self protection move by the PCM.
Check ALL the fuses, both under the dash and under the hood in the fuse/relay box.
If still no good, try deep cleaning the PCM memory - disconnect a battery cable OVERNIGHT at least 8 hours. The memory that it was shorted should erase, letting it get back to normal.
8 HOURS! There are lots of schemes or shortcuts that claim to do it, but they will NOT do what's needed to clear ALL the PCM memory.
Let us know.