My finger constantly hurts .it get discoloured and numb, and often cold..and hurts more with hot or cold water?

Raynaud's phenomenon: This is a vasospastic (spasm of blood vessels) disorder causing discoloration of the fingers, toes, and occasionally other areas, when exposed to temperature change i.E to cold water/air, or even emotional event. When severe, can be quite painful and over time ulcers can occur at tips. Smoking will make this worse. It is treatable...Keep warm/wear gloves. Consult doc for eval/treatment. Good luck.