It seems that you are having sebirrheic keratoses.
Seborrheic keratoses are noncancerous (benign) skin growths .
They often appear on the back or chest, but can occur on any part of the body.
Seborrheic keratoses grow slowly, in groups or singly.
They may be light tan to brown or black. The most common texture is rough, with a bumpy, grainy surface that crumbles easily.
However, they also may be smooth and waxy.
They usually look like they've been stuck onto the skin.
No laboratory test is needed.
Local application of trichloroacetic acid
may alleviate the lesion.
Some time electrocautery or cryotheray may be helpful.
I hope you got my answer..
Dr. Ilyas Patel MD