What should the Imam do if he forgets a verse during Tarawih prayer and remembers it later, and is the complete recitation of the Qur’an in prayer considered accomplished despite this deficiency?

The reader does not earn the reward for completing the Quranic recitation (khatmah) unless they read it in its entirety, including the Basmala at the beginning of every surah except Surah At-Tawbah (Bara'ah). If they forget verses, they must read them to complete the khatmah.

To compensate for forgotten verses in Tarawih prayer, there are two methods: 1. Gather all the forgotten verses and recite them on the last night of Ramadan. This was the practice of the imams of Mecca in ancient times. 2. If the imam remembers a verse he forgot during recitation, he goes back to it and then continues his recitation from where he left off. This is narrated from Ali (may Allah be pleased with him). Sheikh al-Islam Ibn Taymiyyah mentioned that Imam Ahmad and his companions, as well as the people of Mecca, hold the view that reciting only the forgotten verses completes the khatmah and earns the reward.