Short answer: There is no fixed “extra-multiplier” of sin (pāpa) just because it is Paryushan. In Jain Dharma, bondage of karma depends mainly on your intention (bhāva), intensity of passions (kaṣāya), awareness, and whether a vow was knowingly broken.

What makes a fault during Paryushan often heavier

• You are consciously in a period of heightened awareness and restraint. Deliberately doing wrong then usually means stronger passions and disregard, so the bondage can be “heavier.”
• If you have specially taken vows for Paryushan (samayik, fasting, specific niyams) and knowingly violate them, that breach is graver than the same act done without a vow.
• If the act is unintentional and you promptly repent and correct it, the karmic effect is reduced.

How to reduce the fault right away

• Stop the harm immediately and calm the passions.
• Do ālochanā–pratikraman with sincerity, and take pratyākhyān (firm resolve not to repeat).
• If appropriate, add a small tapas (e.g., extra samayik, upavās/ayambil as feasible) and practice kṣamā (forgive and seek forgiveness: “Micchāmi Dukkaḍaṃ”).
• Be extra mindful for the rest of the festival.

Digambar and Śvetāmbara note

• Śvetāmbara observe Paryushan (typically 8 days) and Digambar observe Das-Lakṣaṇ (10 days). Both traditions treat these days as times of intensified sādhanā; the principle above is the same: no automatic multiplier, but deliberate breaches during sacred observances bind heavier karma due to stronger bhāva/kaṣāya.

Helpful guides

• Pratikraman: steps and purpose
• How to perform pratikraman (simple outline)
• Importance and spirit of Paryushan