# It came about

This phrase marks a new event in the story.

# a man full of leprosy

"a man who was covered with leprosy." Leprosy was a skin disease.

# he fell on his face

"he knelt and touched the ground with his face" or "he bowed down to the ground" 

# you can make me clean

The man was ceremonially unclean because of his skin disease. He wanted to be healed. Alternate translation: "please make me clean, because you are able" or "you can heal me so I will be clean"