For the Jews in Jesus' time, this Levitical law was familiar. The woman who suffered for twelve years was forbade to enter the Temple, everything she touched was considered unclean. If she were to touch someone, they would become unclean until evening. Even her own husband, if she were married, would shun contact with her to avoid being unclean. For twelve years she was unable to worship in the Temple. For twelve years she tried everything, spent everything she had, trying to be healed.
Yet she believed that if she could only touch the hem of Jesus garment, she would be healed.
Instead of being made unclean by her touch, Jesus made her clean and healed her. Although frequently when Jesus healed, he would tell the person, "Your sins are forgiven," in this case, he does not. Her issue with blood was not a punishment for sin.
The description in Leviticus 15 of uncleanness is sometimes associated with sin, especially since a sin offering and a burnt offering are to be given. But the reality that the sacrificial system was meant to convey is that we all sin. "All have sinned and fall short of the glory of God." (Romans 3:23)
The sin offerings, whether in chapter 15 or elsewhere, were to help the Israelites recognize their ongoing and constant need for atonement. All the cattle, sheep, and doves in the world are not enough to atone for the sin in our lives. God knew that when he established the sacrificial system. God knew it would never be enough and He already had a plan for the ultimate atonement for sin. But the people needed to learn that their sacrifices would never be enough, that their hearts needed to be replaced by one that seeks after God because "there is none righteous, no not one. No one seeks after God." (Romans 3:10-11)