You can try putting lotion on the outside of the vagina, but I would not put it on your clitoris or any other sensitive area of skin(that can cause an infection), and see if that helps. If you are using condoms, make sure they have some lubrication to avoid drying the skin around your vagina or causing irritation. Some birth controls may also cause slight drying of the skin around that area as well, so if you suspect that your birth control is causing issues, look to see what other method may work better for you.
thank you for anwsering
i feel kinda weird asking this but would if help if i put non-sented lotion down there.
and yes i am sexualy active.
It may be that during your period the area around your vagina is more dry and prone to cracking skin, which in turn can be painful(like many little paper cuts). Try to avoid using any harsh soaps around the area and only use specialized washes meant for that sensitive skin. Are you sexually active? If the above doesn't help, make an appointment with your doctor to find out better ways of dealing with it.