Yep sounds like Raynauds... my Internal Med is a lil rusty, but it can be found by itself (called simply Raynauds Disease) or in a bunch of autoimmune Rheumatologic conditions like CREST syndrome... do you have any other symptoms like joint pain, difficulty swallowing, rashes? Etc
As for the pathophys- im pretty sure its just overactive sympathetic response to cold... you have significant vasoconstriction/vasospasm of blood supply in the distal digits which leads to some transient tissue hypoxia (which is why you see a color change)
By itself, I believe it’s a pretty benign condition… I wouldn’t sweat it.