Connected my ps4 controller to a ps3 now can't connect it back
I had this happen to me. I could not pair my controller to my PS4 because it has a bad micro usb port. You need a second DS4 paired to the PS4, or some kind of input device to do this.
-put unpaired controller into pairing mode by pressing the PS button and Share button at the same time. The light bar will start flashing.
-navigate to Bluetooth menu
-select "Add device"
-select "wireless controller"
-select pair
There may be an extra step somewhere in here depending on what version your PS4 is on.