What’s on our forehead is vital to our lives now and for all eternity. It is not about a physical mark on our foreheads. According to the book of Revelation in the end we, the children of God will be in the holy city, the New Jerusalem, and we will see God’s face, and His name shall be on our foreheads. Rev 22:4, 7:2-4, 14:1. However those who have received the mark of the beast on their foreheads will not have their names written in the Book of Life and will be cast into the lake of fire and be tormented forever. Rev 14:9-11, 20:15.