I would *never* put new, damaged motherboard into a build. That's what the RMA process is for. Inspect the motherboard, take photos showing the unopened, sealed processor in the box so there isn't an accusation of you having damaged the board yourself, and RMA it.
*aside. Why do motherboards ship in unsealed boxes and with unsealed anti-static wrap? It really removes the 1st line of defense a consumer has in proving pre-existing damage.