"he knelt and touched the ground with his face" or "he bowed down to the ground"
# if you are willing
"if you want to"
# you can make me clean
It is understood that he was asking Jesus to heal him. This can be stated clearly. AT: "please make me clean, because you are able" (See: [[rc://en/ta/man/translate/figs-explicit]])
# make me clean ... Be clean
This refers to ceremonial cleanness, but it is understood that he is unclean because of the leprosy. He is really asking Jesus to heal him of his disease. This can be stated clearly. AT: "heal me from leprosy so I will be clean ... Be healed" (See: [[rc://en/ta/man/translate/figs-explicit]])