Final answer:
The nurse practitioner should recheck the patient's TSH values after 6-8 weeks to assess the effectiveness of the Levothyroxine dosage.
Step-by-step explanation:
The nurse practitioner should recheck the patient's TSH values after 6-8 weeks. It often takes weeks or even months for thyroid hormone levels to return to normal and symptoms to disappear, so it is important to monitor the patient's progress. This regular monitoring allows the healthcare provider to assess the effectiveness of the Levothyroxine dosage and make any necessary adjustments, ensuring the patient's thyroid hormone levels are within the normal range.