In the early stages, both can be covered up and masked. Also, in the early stages, the pain can be felt, but as the disease progresses, the body becomes desensitized. Both continue to eat away at the person. With leprosy, there was no cure, and it leads to death. Sin, too, leads to death.
Salvation is immediate and complete.
Consider the leper who hindered the Lord's ministry because of his disobedience. If so, do something about them. It's possible that there is someone like that even in your church. If you would like to see and download the complete Study Guide for Mark, click here on Talks for Growing Christians .