Can moles turn into melanoma if picked?

i have a flat mole on my cheek on my face. i got a tad annoyed with it so decided to get rid of it. i used a pair of tweezers unsuccessfully and only managed to open the middle of the mole. it bled and wept for a bit so i decided to leave it be. i put some aftershave cream on it to clean it out and it stung for a while. the same day the mole has decreased partially in size however has an uneven light brown mark around the mole. i have been to the doctors before and he said that the mole didn't look cancerous. is it possible this mole has turned cancerous or is i