I did this when I was little and ever since it works for small, internal hurting. I also did this on the Waning Crescent:
Put your hand on the place it hurts and imagine a green light around your hand that is healing the spot it is hurting. Then say:
"Pain that wealds its sword within my skin,
Let it be cured by my might,
Thy pain shall not win by the mother goddess,
She gives me health and healing so mote it be."
But remember! Use the basic rules of casting Magick for this to work and the results very.