Hello Demonsoul. :) Not to say the spell didn't have any effect or whatever, though it seems to me like a simple placebo effect. For instance you have a lot of mental stress and, let's say I give you a pill or whatever and my response to you is that you won't feel stressed out anymore. Though in reality it's just a sugar pill, but you believe its actually going to stop you from stressing.
So in your case when you gave the spell to that indiviual, you told him if the results were as predicted he will feel heavy within, correct? So when he came back to you he said "He is feeling a bit heavy in his head." Which seems to relate to the placebo effect, but like I said your spell or whatever could have may or may have not worked. I hope this post helped. :D