Nevus sebaceous on scalp... has it turned serious?

i have a nevus sebaceous (possibly of jadohn) on my scalp since birth. it never gave me any trouble until a few months ago, and now it bothers me everyday. well in laymans terms, a nevus sebacous on the scalp is a hairless patch that can be odd colours, mine is pink! and it's an irregular shape. mine's about 2cm cubed in diameter or so, and it's on the back of my head so i can only see it with a mirror and luckily all my hair covers it as i'm a girl. the problem is, it's now got some kind of lump that has white bumps that i can move and see something that looks like and ulcer underneath?! i've tried savlon, germolene, sudocream and even benovate all too no avail. i'm using special shampoo and i'm careful not to touch it or rub off it, but it still bleeds, flakes and crusts a lot. i also tried to simply rib one of the weird nodules off in the hopes that it would stay gone as it hurts. after profuse bleeding, i saw a bruise and thought yay i finally killed it! but then a few hours later it was back. i just don't understand it. i mean it bleeds for no reason sometimes. very recently i have terrible headaches and i'm so tired i can sleep for days! my only other complaint is reoccuring facial palsy, eye pain and flashing lights in front of my eyes but i ume all of that's not related right? i was just wondering does anybody have any idea what's going on? i feel so worn out it's like i'm a waster and i don't want to bother my family or friends, i mean it's just a patch on my scalp, it really shouldn't cause this much anxiety on my part! i've heard of these birthmarks causing trouble, and i really want to know how and why it happens and what it may mean. anywho, thanks for readin all that babble if you got this far, and thank you to anyone who responds with advice or information on this topic! ;)