When you practice healing on someone in pain, one method is to visualize the moon syllable OM on your hand. It is white in color and its nature is light.

You should then recite the Most Secret Hayagriva mantra, which you need to memorize:

HRIH VAJRA KRODHA HAYAGRIVA HULU HULU HUM PHAT

While pressing your hand on the painful area, keep reciting this mantra.