Hi,
This hard small lump on your areola could be a sebaceous cyst or another skin problem that could also occur on any part of your body. Try to apply hot compresses and antibiotic ointment and see if it helps.
If things don't improve in a week or two,I would consult a dermatologist since it could also be a wart or a mole that can be easily treated.
I don't think that you should be worrying about breast cancer,but it's better to have a physician examine you to make sure that it's nothing to worry about.
Take care....