"Earth makeup" refers to the male protagonist's carefully painted remains of the deceased. It is the last farewell makeup in the world, symbolizing ending, repair and silent protection.
"Weiyang yarn" refers to the wedding dress (or other clothing that symbolizes rebirth) designed by the heroine, which means "unfinished new beginning" and "endless hope". It also metaphors the struggle of her design career and her longing for a better future.
The whole thing implies the extreme opposition between the two professions (death and rebirth, ending and beginning), and their intertwined destinies are like applying makeup/making yarn to each other, but in the end it is an unfinishable ritual, leaving only regrets.
Intention: Regret