Bruises Before and After Mentrual Period

Many people are experiencing this dark bluish violet-to-black bruises underneath the skin usually on the thighs and arms is called Hematoma.
This occurs when there is blood clot from a damaged small blood vessel called asterioles and venutes. A painful small palpable bump is felt when the bruise is pressed.

This should not alarm those women experiencing hematoma, which is common during menstrual period because of hormonal influence. It is also sometimes related to sensitivity to strong household chemicals like insect spray or repellents.
Just avoid bumping into things especially during menstrual period and avoid exposure to household chemicals.
Also, take vitamin c supplement to increase the integrity of blood vessels.