The only person that is twisting the interpretation is you. I've asked you to show me where the manga says the pain will kick in later and you have failed to do that.
Your mistake is you trying to make this out to be something is not. The medicine will instantly heal Zoro and once it runs out he will have double the pain. Since the healing is instant the pain will come quick since the medicine won't take a long time to heal him.
Your mistake is you trying to make this out to be something is not. The medicine will instantly heal Zoro and once it runs out he will have double the pain. Since the healing is instant the pain will come quick since the medicine won't take a long time to heal him.