Ideally this consecration should be made after the Novena to the Holy Face is prayed for nine days.
Act of Consecration to the Holy Face
O Lord Jesus, we believe most firmly in You, we love You. You are the Eternal Son of God and the Son Incarnate of the Blessed Virgin Mary. You are the Lord and Absolute Ruler of all creation. We acknowledge You, therefore, as the Universal Sovereign of all creatures. You are the Lord and Supreme Ruler of all mankind, and we, in acknowledging this Your dominion, consecrate ourselves to You now and forever.
Loving Jesus, we place our family under the protection of Your Holy Face, and of Your Virgin Mother, Mary most sorrowful. We promise to be faithful to You for the rest of our lives and to observe with fidelity Your Holy Commandments. We will never deny before men, You and Your Divine rights over us and all mankind. Grant us the grace to never sin again; nevertheless, should we fail, 0 Divine Savior, have mercy on us and restore us to Your grace. Radiate Your Divine Countenance upon us and bless us now and forever. Embrace us at the hour of death in Your Kingdom for all eternity, through the intercession of Your Blessed Mother, of all Your Saints who behold You in Heaven, and the just who glorify You on earth. O Jesus, be mindful of us forever and never forsake us; protect our family. O Mother of Sorrows, by the eternal glory which you enjoy in Heaven, through the merits of your bitter anguish in the Sacred Passion of your Beloved Son, our Lord Jesus Christ, obtain for us the grace that the Precious Blood shed by Jesus for the redemption of our souls, be not shed for us in vain. We love you, O Mary. Embrace us and bless us, O Mother. Protect us in life and in death. Amen. Glory be to the Father, and to the Son, and to the Holy Spirit. As it was in the beginning, is now, and will be forever. Amen.Also See: Devotions to the Holy Face and its Special Significance for this Lent
Link for Complete Novena Nine Days
Seeking the Face of Christ During Lent Holy Face Devotion Defenders of the Holy Name + Also See: Penance, Penance Penance Why are the shepherds silent