Answer

Yes, you can take Chovihar Pachkan at night after having taken Tivihar Pachkan during Pratikraman, provided you are sincerely able to follow the stricter rule.

Explanation

In Jain practice:

• Tivihar means renouncing food and certain drinks, but water is generally allowed within the permitted time.
• Chovihar is stricter: after taking Chovihar Pachkan, one renounces food as well as water until the Pachkan period ends.

So if you first took Tivihar Pachkan, and later decide to observe Chovihar, you are increasing your restraint. This is generally acceptable because you are moving from a lighter vow to a stricter vow.

However, once you take Chovihar Pachkan, you should not drink water afterward until the vow period is completed.

Spiritual Understanding

In Jain Dharma, Pachkan is a conscious vow of restraint. The main thing is clarity, sincerity, and careful observance. Taking Chovihar later is spiritually beneficial if done with proper understanding and without carelessness.

Takeaway

You may take Chovihar Pachkan at night after Tivihar Pachkan, but only if you are ready to fully follow Chovihar from that moment onward. For exact local practice, it is best to confirm with your Guru Bhagwant or knowledgeable elder in your Jain sangh.