Percy jackson fans, why does nectar hurt so much when its used to clean out wounds?

I can drink nectar as I am a demigod and it doesn't hurt to drink but if I drink too much it will kill me, but when nectar is used to clean out a cut why does it hurt so much? Chiron put some nectar on my stab wound and it really hurt (Annabeth says I was crying but I wasn't!) but it's healed really good. Our blood is half mortal and half god so it shouldn't hurt that much does it? and don't say I am weak as it hurt Annabeth when Ethan stabbed her and Percy in the demigod files said it burnt when that underworld monster got him