red dots ...

I don’t really know the best way to explain this but I’ll try my best. OK so a few years ago I noticed this little red dot on my index finger. When you put pressure on it or beside it, it turns white then comes back once the pressure is gone. I’ve always wondered what it could be caused from? Maybe lack of nutrition? Or popped blood vessel? I’d really like to know what they are! I have 5. On my index finger, in between the knuckles on my pinky and ring finger, on my left arm, below my left eye, and on the tip of my nose. (ok that one doesn’t count anymore cause I got so annoyed with it that I cut it away..lol) Anyway, they aren’t bumps, their completely smooth and barely noticeable. But I still want to know what they are! lol Any ideas?