I Have Had A Cafe Au Lait Birthmark Above My

I have had a cafe au lait birthmark above my left part of my upper lip since birth. A couple years back i had a skin biopsy where a section was taken for analysis to see if the birthmark could be removed. Currently that area has healed and is now my natural colour of pigmentation. My question is, what does this tell me? Does this mean the birthmark is not deep and can be removed by a series or one larger skin biopsy? Is that possible? Thanks!