Thanks for the question.
Yes, sins leave their mark, and there is the demand for justice to make right for their wrongs.
Think of how a family can forgive someone for having murdered a family member, but the perpetrator still needs to do the time for the crime. That is why the Church has always taught that sins, even those that have been sacramentally forgiven, require expiation.
- So when we sin, is there hope that we can escape punishment for our transgressions?
Absolutely, there is hope! First, Peter tells us love covers a multitude of sins (1 Peter 4:8, cf. also Luke 7:47 and James 5:20), and then we know that doing penance is an act of reparation. So fasting, prayers, good works, efforts to make things right, all have merit in God's sight.
Think of how Zacchaeus promised to make good on all he did wrong (cf., Luke 19:8).
Lastly, there are many indulgences which the church has given to the faithful to remit temporal punishment due to sin, because there is a treasury of grace that Christ has effected through His Body the Church, and He desires to dispense that grace to all who dispose themselves to this great Mercy. Some things which have indulgences tied to them are the daily recitation of the Rosary, reading of the Scriptures, pilgrimages, Divine Mercy, and much more.
There is no reason for us to get hung up on the concern, that we did so much wrong, that we will be in Purgatory forever. There is too much grace available to us to worry about that. Instead, focus on loving God, being grateful for his kindness and mercy, and then bring that love to others.
He will set you free in every way from your past, but don't be surprised if you feel worse before you feel better. Sometimes when you realize how much God truly loves you you can't stomach the ways you failed him.
Ironically, that pain is an indication that your love for God is growing. It is like a growing pain, a little like Purgatory being lived out, in the here and now. Just wipe your tears away, kiss the heart of Jesus, and help someone else who God puts in your path.
In some way you are meant to pay this forward.