When the corruption is in the start stage and slowly grew with time, he could feel a faint burning sensation in his energy network.
All of his meridians were being refined by this energy. When he was full of corrupt energy, the refining went to the point of literally burning his energy network. He felt injured and weak. The pain constantly distracted him.
So, all he could do was suppress it.
When he suppressed it, the burning pain reduced by a lot, but he could feel that his energy network was still under pressure because of it as his own energy needs to suppress the corrupt energy.
When he finally released it into the pillar, he could feel that his body changed a bit. Not only did his meridian network was tempered, but the more he kept the energy in a suppressed state, the more his blood and muscle fibers also being slowly treated with it.
