My mother told me once upon a time that if you picked at a mole on your body, and it started to bleed, then you would get cancer. Is this true? Can someone really get cancer if they pick at a mole and it starts to bleed?
My mother said the same thing. I have also heard that moles with a tendency to bleed are more likely to be cancerous - i.e. picking a mole to make it bleed will not change it from a benign to a cancerous mole, but that the fact that it is prone to bleeding is a bad sign.
Disclaimer: This all just stuff I have heard. I am neither a doctor, mother or a mole - so what do I know 
I have a mole on my neck, which I’ve cut and caused to bleed while shaving dozens of times over the last 30+ years. I did not get cancer.
Sounds like an old wives’ tale.
(disclaimer: I am not a doctor. etc. etc.)
IAAD.
Skin lesions which bleed should be evaluated. They are at a higher risk for cancer than many other lesions.
If mild to moderate manipulation (picking) makes a skin lesion bleed, this could indicate it’s at higher risk for cancer also.
But the picking doesn’t cause the cancer.
Cutting skin or skin lesions with a knife/razor/scalpel will cause bleeding, as will severe manipulation (picking). This generally has no bearing on cancer at the site of cutting.
I guess I’m repeating Qadgop to a point here but I was just at the doctor yesterday getting a dermatologist referral for some moles my wife wants checked out. The first question the doctor asked was “Have they been bleeding?”
So I’d guess bleeding moles is a classic sign of trouble but artifically making them bleed (poking them with a needle, etc) isn’t want makes them cancerous.
I clicked on this assuming you were some British person having trouble with burrowing animals.
Do you know the acronym TMI perhaps?
So long as we’re asking questions about moles, I’ve got one.
Say you have a mole with a thick, dark hair growing out of it, and you wanted to get rid of the hair. Is hair growing from a mole a sign that it is or isn’t cancerous, or is it just gross? Would shaving the hair do anything to make the mole more likely to be cancerous? What if you went with something more permanent like laser hair removal? Would that work on a hair that comes from a mole?
This is the first hitI got when I Googled “Warning signs of cancer”
(emphasis added)
I can see how mothers everywhere could consider “bleeding” to be an “obvious change.”
If you have a history of skin cancer, you want to get ANY suspicious-looking spots/freckles/moles, etc. checked out. I had an appointment yesterday for a spot on the sole of my foot that looked sort of scary. What a relief it was to hear the dermatologist (knowing I had 3 melanomas in the last 10 years) say “Oh, that’s not anything to worry about.”
I had a dermatologist appointment recently that ended with the diagnosis: “You’re a collection of meaningless symptoms.”
Delivered, I’m happy to say, with a smile.
Glad I wasn’t the only one.
IANAD, but I do have more moles than a British lawn. I’m evaluated quite often, and have had about a dozen removed and biopsied (no malignancies, knock wood!) None of the ones flagged for removal had hair, but several of the ones I still have grow hairs, and the doctors have never mentioned hair as a warning sign of anything. Size, shape, bleeding, pain, change over time and more than one color on a single mole, yes, but hair no.
Not moles so much, but my dentist told me not to bite my lips (I have a bad habit of chewing my lips when I’m nervous, without being aware of it), because he said the healing tissue could eventually form a cyst, and possibly lead to oral cancer. Was he merely trying to scare me?
I did too! In my case it’s because I have noticed some mole holes in my front yard over the last few days.
Ditto to thinking this was about some more animals that Britain got but Ireland lacks (to the best of my knowledge).
To the OP, my sister tore one completely off my face with her nail when I was a kid, still here over twenty years later. Actually a bit better looking too for it 
My derm told me the hair in the mole is actually a good sign and that it means the mole is healthy. If the hair falls out that could be bad.