In the Bible, St. Paul gives us a list of grave sins. He states that anyone who commits these sins shall not enter the kingdom of God.
“Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness, idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, (HERESIES), envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God” (Galatians 5:19-20).
Mortal sins destroy the grace of God in the heart of the sinner. By their very grave nature, a mortal sin cuts our relationship off from God and turns man away from his creator.
Paragragh 1472 Catholic Catechism: "To understand this doctrine and practice of the Church, it is necessary to understand that sin has a double consequence. Grave sin deprives us of communion with God and therefore makes us incapable of eternal life, the privation of which is called the “eternal punishment” of sin.
On the other hand every sin, even venial, entails an unhealthy attachment to creatures, which must be purified either here on earth, or after death in the state called Purgatory. This purification frees one from what is called the"temporal punishment" of sin.
These two punishments must not be conceived of as a kind of vengeance inflicted by God from without, but as following from the very nature of sin. A conversion which proceeds from a fervent charity can attain the complete purification of the sinner in such a way that no punishment would remain."
From my understanding the Church affirms my earler post. “That is why those who in ignorance follow after heresies will suffer for the heresy, even though they thought the heresy to be truth, for they had the opportunity to know the truth.”
From the New Testament Greek Lexicon based on Thayer’s and Smith’s Bible Dictionary plus others; this is keyed to the large Kittel and the "Theological Dictionary of the New Testament.
Punishment: Execution of a sentence, punishment to suffer punishment
I would take no comfort in suffering punishment even if it was temporal.