What Are The Symptoms Of Cervical Melanoma?

My doctor has scheduled me for a colposcopy to rule out melanoma of the cervix, due to a dark spot on my cervix and strong family hx of melanome (grandfather and great grandfather)

is there a blood test for melanoma and is this the best pre-test? I did have a pap smear today as well. Past two months of large amount of vaginal bleeding and cramps. What are the symptoms of cervical melanoma ?