I have a 5mm black mole (i have brown skin) on my shoulder since i was a teenager. i havent noticed big size change, but it has black specs inside of the mole. the borders are not perfectly round, but are defined.are spots inside of a mole abnormal?

Only under a microso: there is no 100% sure way to distinguish a benign nevus from cancer by looking at it. Lets use the acronym ABCDE: Asymmetry (no), Border uneven(yes), Color not uniform (spots?), Diameter >6mm (no), Evolving/Growing in size; (no) . Is there a family history of skin cancer? You need to have it looked at by a primary care Provider. They will either monitor it, or do a biopsy.