What Causes Dark Colored Vaginal Labia?

when i was a kid i got Allergy on my vigina, i was have pain when i was urinate , i covered , but day by day my vigina color changed , and the outer lips got smaller , like it seems my vigina has no outer lips , plus it's dark , actually i am 23 now , and still virgin , cause i feel shy cause what i have , i hope i could get a sloution for this problem...sooooooon