Are all black moles cancerous? smaller than the shape of a pencil eraser. not bumpy, almost looks like a circle. on skin layer that isn't expose much

Moles : Not all dark moles are cancerous, but should be evaluated by a dermatologist especially if it is new or has been growing or changing in appearance. Good luck!

NO: Not all black moles are cancerous, but if they are changing (growing, changing shape, getting bumpy) they need to be looked at by a doctor who is good at diagnosing shin cancers, especially melanoma. If you are one who does at lot of suntanning or use tanning beds, please reconsider this activity!

Not all, but some : Black moles are very worrisome for skin cancer, especially melanoma. It is hard to answer your question without an examination. It is concerning when moles change - change in size, color, become irregularly shaped, itch, bleed. Most moles are relatively easy to remove and test. Please see your primary doctor or a surgeon to see if this needs to be removed and tested.