White bump on outer edge of lip?

i have this bump on the outside edge of my lip and it has been there since december of last year..when it first appeared, i popped it and it left a reddish mark where it was, then suddenly reappeared... but now it seems permanent....the only kind of medicine ive tried was blistex ointment but it doesn't help. the bump is white looking and its not squishy like a regular pimple, its not painful at all.. when i try to pop it now.. all it does is bleed.. what could this possibly be? its really frustrating me :(