Suggest Treatment For Bump On Right Outer Vulval Lip

hi, i'm 17 and a virgin and i have had a worry for some time, i have a small bump like pimple on my right outer vulval lip, it is skin coloured, looks just like it is just a bit of skin sticking out a bit and if i squeeze or catch it, it's a bit sore and bleeds it's as though its just a bit of skin, also i don't see it there all the time, its normally only there around the time of my period and then goes down again after. is this anything to worry about?