Lin Chen received the token given by Sang Daoqing and, after sufficiently showing his gratitude, he finally left the Wei Family Pharmacy.
The reason Lin Chen went out of his way to get a letter of recommendation from Sang Daoqing was naturally to infiltrate the Wei Family.
With the Hidden God White Jade Stem in the Yuwen Family's possession, and Lin Chen having no connections with them, it was impossible for him to obtain it. Similarly, Shangguan Wenyin was an enemy of the Yuwen Family, so there was naturally no way through there, either.
The Wei Family had a close relationship with the Yuwen Family, almost like one big family, so Lin Chen concocted a plan to infiltrate the Wei Family under the guise of an alchemist and then find an opportunity to transfer the Hidden God White Jade Stem from the Yuwen Family.
Although there was a certain risk and success was not guaranteed, not trying at all would mean never succeeding!