Hi, there's a mole on my lower back that I accidently rubbed it off, raw, in the military from my rucksack. There was a slight scare but gone. Few years later it grew back and turned really black and bulged out. It would hurt and bleed but after a few weeks it fell off. Now two years later it has done the same thing again and is black and raised and hurts. Will moles just bleed periodically if they're rubbed off or is this something more serious? Thanks for the help