If a Jew does something knowingly against the law, is there any prayer or ritual to ask G-d’s forgiveness?

The specific action that prompted this: I’m having my cat spayed. My understanding is that this is against the law. I feel guilty and conflicted, but also don’t think in the modern world I can allow my cat to have kittens I can’t care for or find homes for, and I obviously don’t want to give up my cat.