Thanks for the query.
on shin is due to crushing of your tissue in between the shin and the external pressure. Some blood vessels get ruptured during the time and blood gets collected in between the tissues. That is how a bruise occurs. The collected blood is slowly broken down to it's constituents and removed from the site over a period. Then the bruise disappears.
I presume you do not have any problem in walking or playing. Since it has happened around 2 weeks back, the colour would have become normal now. The bump which remains on your shin will go over some time. No treatment would be required for the same. You can apply hot water compression to the swelling, which would speed up the process of healing.
Hope I have answered your query.
Let me know if I can assist you further.