Penance
This is the Sacrament in which sins committed after Baptism are forgiven. It results in reconciliation with God and the Church. (US Catholic Catechism for Adults, Glossary)
An Act of Contrition
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.