The effects of karmas of the past are necessarily to be gone through. But the intensity of suffering has every chance of getting reduced by divine grace based on the strength of good karmas currently being done (like forgiving the people who wronged you).
We have karma swatantra (freedom to do actions based on our self will) but we do not have bhoga swatantra (enjoying or suffering the effects of past karmas at our choice). We have to only wait for divine grace.
Past karmas’ effects may still manifest in us as illness or disease, but by divine grace, the intensity of suffering may get reduced.
Ma Sardada Devi used to say that if your karma phala was that you should die by the bite of a poisonous snake, by divine grace, it might get changed to a minor wound caused by the pricking of a thorn.
Let us see a hypothetical example. A person, out of a spurt of anger, killed his neighbor and his 2 children by scheming a car accident. For 6 months, the police could not get any clinching evidence to locate the murderer. Hence this person was neither suspected nor arrested. He lead a happy and normal life for 6 months and was very hopeful that he would never get caught.
But after 6 months, a new Inspector took charge of the case and he was extremely smart to probe deeper into the case and the forensic reports. He accused the person of murdering the neighbor and arrested him. The case dragged on for 1 more year and he remained in jail as he could not gt bail. His lawyer argued strongly that his client was innocent. However they lost the case and he was sentenced to death. He appealed to the higher court. Another 1 year in jail. He was reading spiritual books from Jail library. His mindset went through a change.
Despite his lawyer’s advice, he pleaded guilty. The high court cancelled his death sentence and he was imprisoned for life. He behaved very well in Jail and was doing whatever service he could do there. The jail authorities recommended for reducing his period of imprisonment. He was released on account of good conduct after serving 7 years of imprisonment.
Even though he admitted his guilt and repented for it, he did not get released from Jail. He had to go through the imprisonment, but he was saved from death sentence and also his term in jail got reduced.
Karma and dharma more or less work like the above example.