After confessing your sins to a priest, here are a few options of what to say next.
One of the necessary elements of the sacrament of confession is reciting an act of contrition. A priest will usually prompt the penitent after they confessed their sins by saying such words as “Now say your act of contrition.”
The Catechism of the Catholic Church offers a brief explanation of what this is: “Among the penitent’s acts, contrition occupies first place. Contrition is ‘sorrow of the soul and detestation for the sin committed, together with the resolution not to sin again.'”
Essentially it is a personal proclamation that you abhor the sins you confessed and are resolved to lead a life of virtue, doing all that you can to stop committing those and any sins in the future.
Strictly speaking there is no one formula that a penitent must recite. The person may use their own words, or use a traditional act of contrition. The important part is that the individual has a “sorrow of the soul and detestation for the sin committed, together with the resolution not to sin again.”
For those who need a prayer handy in the confessional, here are a few different options that the Church offers to the penitent.
My God, I am sorry for my sins with all my heart. In choosing to do wrong and failing to do good, I have sinned against you, whom I should love above all things. I firmly intend, with your help, to do penance, to sin no more, and to avoid whatever leads me to sin. Our savior Jesus Christ suffered and died for us. In his name, my God, have mercy
Wash me from my guilt and cleanse me of my sin. I acknowledge my offense; my sin is before me always. Psalm 51:4-5
Father, I have sinned against you and am not worthy to be called your son. Be merciful to me, a sinner. Luke 15:18, 18:13
Lord Jesus Christ, you are the Lamb of God; you take away the sins of the world. Through the grace of the Holy Spirit restore me to friendship with your Father, cleanse me from every stain of sin in the blood you shed for me, and raise me to new life for the glory of your name.
Lord God, in your goodness have mercy on me: do not look on my sins, but take away all my guilt. Create in me a clean heart and renew within me an upright spirit.