There is nothing you can do at this point since it has been 3 years. But I would take him to his doctor and let his doctor check this out so that he is aware of this, and if he feels he should he may order a ct scan to see if there is a fracture of some sort and at that point can determine if there is anything. Other wise there at this point there is no home treatment. But to be safe.. do take him to be seen.
Hope this helps.
