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Pregnancy can cause oedema over legs which is generalized and not a local swelling.
can be another cause of swelling but in that you can see the veins which are bluish in color.
I think this is a local muscular condition or can be due to allergy and skin rash
I hope you are not doing waxing or using any creams or razor for hair removal
as they can cause skin bumps.
It is better to consult a dermatologist