The sin is forgiven by the priest, yes. However, some temporal punishment is also required to purify yourself before you can be in God’s presence. While the penance a priest assigns can help, it is not intended to substiture for this temporal punishment.
This temporal punishment can include your soul spending time Purgatory after your death. It can also include suffering in this life. In fact, Catholics have the best answer to the eternal question, “Why do the good suffer?” To be purified in this life.
So when things go bad, when you feel pain, physical, mental or spiritual, offer it God as a penance for your sins. This is how saints are made.
This is where we get to the subject of
indulgences. An indulgence is the partial or complete forgiveness of the temporal punishment for sin because you have engaged in some activity the Church deems worthy. But there are many conditions involved with indulgences and they are, in fact, quite difficult to earn. That is mostly because in general one must not have any attachment to (that habitual) sin, even venial sin. A state most of us are not in very often.
By the way, I understand that Pope Benedict goes to confession every other day, as did Pope John Paul II. There must be something to the idea of frequent confession.
