What white worm lives on or in the body?

It depends where in the world you are located. There are a variety of worms/parasites that will live in/on humans.

For instance, there is a fly in Brazil that carries its eggs under them but will land on humans, release the eggs and they will bury in your skin as well as hatch very quickly after being laid.

In the US this is common of the botfly. You may hear of the worms being called wolfs or wolf worms.

If you go to google.com and type in human worms there should be a variety of information you may be looking for.