Pain Exchange System: the School Beauty Relies on Me to Relieve Pain

My name is Chen Jin, I get stronger by being beaten, and the school beauty relies on me to relieve pain. After being beaten into the equipment room by the school bully, I bound the [Pain Exchange System]. The harder the pain, the stronger the exchange? Until the school beauty Lin Zhou came to visit. She tore off her perfect disguise, trembling in my pool of blood and whispering: "Don't move... Let me stop the pain." She sucked away my pain and revealed morbid satisfaction. I used my broken leg in exchange for her secret of breaking down and tearing up the test paper, but in exchange for her deeper coveting - "Your pain is my nourishment." She crushed my hope, her eyes as hungry as an animal. On the rooftop, she grabbed my neck and fell: "A defective product is worthy of touching my 'source'?" After my rebirth, I realized that this link in the name of pain was her father's craziest experiment... - Her painkillers, it's my bones burning.