The healing was done in private (7:33; see 5:40–43; 8:23). This likely helped prevent people from spreading strong excitement about Jesus as the Messiah (God’s chosen king; see 3:11–12; compare John 6:15).
Jesus also used saliva in another healing (Mark 8:23), when he put it on a man’s eyes to heal his blindness. The use of saliva for healing was common in the ancient world. People believed it could help heal certain conditions.