The perineal raphe extends from the anus, through the mid-line of the scrotum (scrotal raphe) and upwards through the posterior mid-line aspect of the penis (penile raphe). It is observed as a noticeable line. It is the result of a fetal developmental phenomenon whereby the scrotum and penis close toward the midline and fuse. The resulting ridge of tissue is normal.
i have one as well you can see it goes all the way down i think it is very normal.