Causes: It is caused by yeast called Malassezia, which normally exist in small numbers on the skin. Certain conditions however, can cause the overgrowth of the yeast, causing the development of white and reddish-brown spots on skin.
The 3 men all escaped and made it back to the Britain.   The Great Escape shown in the film happened in March 1944 having been planned first in January 1943. It consisted as per the film of 3 tunnels Tom Dick and Harry, Tom being discovered by the Gestapo.
The escape network was not literally underground nor a railroad. It was figuratively underground in the sense of being an underground resistance. It was known as a railroad by way of the use of rail terminology in the code. The Underground Railroad consisted of meeting points, secret routes, transportation, and safe houses, and personal assistance provided by abolitionist sympathizers.