After exchanging blows with Evil Eye Witch, Lin Jin was considered to have dabbled in the art of psyche attacks and defenses. Quite honestly, Lin Jin's had an innate talent in mental cultivation, which placed him in a headstart.
He had the Museum of Deadly Beasts, so every time he ventured inside to check up beast descriptions, treatment methods, or evolution methods, he had to use his psyche.
The repeated process ended up fortifying his psyche significantly.
Like a young man with a strong body, a great spirit, and incredible talent, wouldn't a person like this be able to grow exponentially when he finally decides to practice martial arts?
That was a given.
Evil Eye Witch's attack had opened up a new door for Lin Jin; it was like a knife that pierced through a paper window, revealing a whole new world behind it.