Picked off mole (maroon, black tissue initially mistook as blood blister)what i realized later looked exactly= nodular melanoma. would bx still be accurate for diagnosis since i picked off visible lesion.

Biopsy: I think an excisional biopsy - removing the remnants and any surrounding tissue is appropriate - first off - if it is a melanoma - a wide excision is recommended anyway. Secondly - while you may think you got everything - there are probably cells remaining. good luck

Biopsy needed: Yes, if this is in fact a melanoma, a biopsy would still show it even though you pulled off the top layer. If it's not a melanoma, a diagnosis could still possibly be made. It would be uncommon for you to be able to simply pull off a melanoma however. See your dermatologist to be sure.

See a dermatologist: If you have the mole, I would recommend seeing a dermatologist to see if they can send it to a dermatopathologist to evaluate.