Hi, I m 19 and currently having unprotected sex with my partner of three months, his last sti check was November and came back all clear. He is my first partner which I ve had unprotected sex with it. But last night when I came out if the shower I noticed a purple lump on my left labia minora . It is painless, and not really even that hard when I press on it. I m afraid it may be something to worry about, however when I finished my routine afte the shower it s just poppe naturally, and seeped a true red colour of blood. It stopped after several moments. When I checked it later in that night it looked like almost a cut, as the opening of -let s say the blister- is half moon in shape. My inital thought is blood blister due to vigorous pressure on the area from sex and masturbation. but one can never be too sure. Should this be something I get checked by my GP?