Scared of melanoma! (serious question)?

Ok, so I have always been very healthy but all of a sudden I have this small black mole on my lower leg that just popped up overnight. At first I barely noticed it, but now it hurts and kind of feels like my whole leg is sore. Could it be melanoma? I'm very scared because I do not have health insurance and cannot see a doctor for this (which I know I should). How much would it cost to go to a dermatologist and have them just look at it/take a biopsy? I am getting married in a few months and do not need this extra stress!