I imagine it’s a side-effect of vasoconstriction - there is not enough blood getting to the very ends of your arteries and into the capillaries where oxygen, nutrients, no waste are exchanged with the cells. If you smoke almost every day you might develop a chronic condition called Peripheral Venous Insufficiency. It causes several problems, but one is that your feet and lower legs get much more easily infected. If you smoke less regularly you could still get acute systems such as cold feet, discolouration.
Your feet are healing after a few days of not smoking, most likely because the vasoconstriction has stopped and blood it getting all the way through to do all the good stuff it does. That suggests your vein problem has not yet become chronic, but over time it still could. If you get swollen feet, ankles, or calf as well, either when you smoke or after, then it is almost certainly a vein-type problem.
Interesting one effective treatment for all this is a moderate daily dose of Cialis (other erectile dysfunction drugs like Viagra are not effective in the same way). If you can get hold of Cialis, try taking one all the days that you smoke. Not only will you have no problems with stim-dick, but likely you won’t get these feet symptoms either.