Did I short my phone?

While repairing my iPhone from a broken screen I decided while I’m In there I needed a new battery, so I follow the steps to a tee and with the new battery in the part of my phone right above the connectors for the display immediately becomes extremely hot to the touch. But there should have been no short I only used the plastics poker to release the ribbon cables. And I tried my old battery a known good and it wouldn’t turn on. Was it the battery or me?