Why didn't Xue Jian become Miss Tang?

He was given by Pan Ya's father to Tang Lao's boss, and she was born as a fairy fruit in Yao Xi, so her hair grew in spring. Later, the poisonous people raged and the old head of Tang died. Xue Jian told her the truth about the five poisonous beasts, so she is not from the Tang family. But her second uncle later failed. Yao Xi is Erigeron's wife.