With the help of the Legion of Super-Heroes from the future, Clark extracted Brainiac from Chloe. She was fully-recovered with most of her prior memories, including knowledge of Clark's secret, intact. However, Chloe had indicated that she does not clearly remember the time period leading up to the wedding.

Does Chloe learn Clark's secret again?

After unintentionally following Clark to the Fortress of Solitude, Chloe knew that there was more to his secret than she realized. After saving Chloe from freezing to death in the Fortress, Clark finally told Chloe everything in the season 5 premiere — and from then on, she served as Clark's closest ally.

Does Chloe regain her memory of Clark?

The Legion was willing to sacrifice Chloe's life to defeat Brainiac, but Clark convinced them to work together to save her. They successfully removed Brainiac and cured Chloe, in the process, restoring her memory of Clark's secret.