You are forgiven, when the priest gives you absolution. If you were really forgetful and did not say your penance, you are still forgiven. The problem is that sin makes us unclean. After we are forgiven, there is the stain of sin that requires penance. Nothing unclean ever goes before God. If we are not sufficently clean, when we leave this life, we will be cleansed. If we knowingly totally reject God, we won’t need this step. This state of cleansing was given the Traditional name of Purgatory. Using this name has continued to cause arguments among Christians. This name per say is not in the bible, but there are references to a cleansing. You can go into the library here at Catholic Answers and read about it.
