Thank you for the information,
There are some common causes of such toe discolouration along with numbness.The common ones are fungal infection, vascular disease, decreased blood supply, lepsrosy, diabetes, frostbite, etc.
As per the symptoms described by you, the chances of fungal infection may be ruled out furst which may cause such discolouration of toe and nail.The antifungal drugs are need to control such symptoms.It is usually taken for a few months.
The other possibility could be the vascular disease.The decreased blood supply may also cause such symptoms of pain, numbness with discolouration.It should be examined by doctor and investigated.
The other causes should also be ruled out like diabetes, leprosy, frostbite etc though the chances are less.
Here is the link for more information
causes of toe numbness
Let me know if you have any doubt.