‘And it came about, while he was in one of the cities, behold, a man full of skin disease, and when he saw Jesus, he fell on his face, and besought him, saying, “Lord, if you will, you can make me clean.” '
All background information is suppressed in order to focus entirely on the man and his condition, although Luke probably expects us to recognise that we are still near the Lake of Gennesaret. (It may also have been in order to prevent embarrassment to a well known figure. The man was still open to rebuke for having ventured into the city while ritually unclean). He was ‘full of skin disease', a clearly severe case. (‘Full = pleres, a term regularly used by medical men to describe the progress of a disease). And now he was meeting someone Who was ‘full of the Holy Spirit' (Luke 4:1). As being unclean he was not supposed to approach anyone, least of all a prophet of Israel in Whom was the Holy Spirit. But when he saw Jesus, concerning Whom he had heard so much, he fell on his face before Him. In his heart he knew that this man could help him.
And he begged Him saying, ‘Lord, if you will, you can make me clean.' His doubt was not whether He could do it, but whether He would. For many turned away from him in disgust when they saw him. It was a cry of faith, and yet of anguish.
Notice his desire, to be made ‘clean'. This is the thing above all that hurt him so deeply, not so much the dreadful disfigurement, but being unable to approach God's house and being unable to be in contact with fellow human beings.