Hello there, thanks for writing in. There could be two possibilities for bleeding inside labia. One is your tissue could be more fragile than normal and any mildest trauma in the area could result in bleeding and an eventual lump. Another is a possible endometriosis, which means abnormal location of endometrial tissue ( uterine lining )in the labia ( anywhere outside uterus ). But if is endometriosis, it will be accompanied with cyclical pain as you bleed every month and swelling increases periodically. However, rarely it could be a cyst which bled into itself. The diagnosis may be helped by sending the excised tissue for histopathological examination. Hope this little information is helpful. Take care.