I'm guessing you're dark haired, but probably fair-skinned?
If you are, the dark spots are not necessarily clogged pores, but hair roots and/or an awaiting blunt regrowth. The best solution for this is something like waxing or electrolosis. Or perhaps cover-up methods, like fake tan.
If you honestly think it's clogged pores, then you can get gentle exfoiliating mitts that are also useful for blood circulation in the skin. They're not too rough. And a skin cleansing bath or shower wash containing Tea Tree oil. This is good for unclogging skin pours and promotes clear skin.
Nevertheless, you shouldn't be embarrased- no one has the proverbial 'Perfect Skin' and no one really looks at legs. Most people's vision is directed towards the face & eyes, so I bet no one actually sees what you see. Most of us are very self-critical and the small things that no one sees, can be the things that bug us the most.