For souls who grieve having offended the God they now love perfectly
From the Novena for the Holy Souls in Purgatory
Sacred Scripture: Romans 8:18
Meditation for Day 4
St. Alphonsus reveals a particular anguish of the holy souls: they now love God with a love freed from all earthly weakness, and this very love makes the memory of every past offense feel acutely painful. They know they once turned from the God they now long to embrace. St. Paul consoles us that the sufferings of this present time are not worth comparing with the glory that is to be revealed (Rom 8:18) — and this is true above all for souls in Purgatory, whose suffering will open directly into the beatific vision. Today we pray for those who died loving God but weeping over a life of many sins.
Daily Novena Prayer (recited every day)
Closing Prayer
O God, the author of mercy, the lover of the salvation of mankind; we address thy clemency, in behalf of our brethren, relations, and benefactors, who are departed this life, that by the intercession of blessed Mary, ever virgin, and of all the saints, thou wouldst receive them into the enjoyment of eternal happiness; through Christ our Lord. Amen.
Concluding prayers: Many novena traditions add one Our Father, one Hail Mary, and one Glory Be at the close of each day's prayer.
Source
https://www.ewtn.com/catholicism/devotions/novena-for-the-holy-souls-in-purgatory-286