This sounds like you have a few moles on the soles of your feet. Moles are caused when collections of pigmented cells called melanocytes collect under the skin. Moles occur in virtually all people, and they are generally a normal finding. Moles can also occur on the soles of the feet and the palms of the hands, just like anywhere else on the skin. Having a mole on the bottom of your foot is no different than having one elsewhere and doesn't mean anything particular, such as that you are at higher risk of skin cancer.
Nevertheless, the reason to keep an eye on any mole is that they can sometimes transform into melanoma, which is a serious form of skin cancer. If you notice that one of your moles is changing in any way, that would be the sign to go see your doctor
. In particular you should be on the lookout for any mole that is asymmetric (the two halves different from one another), has irregular borders, has changes in or multiple colors, is larger than about the size of a pencil eraser, or is elevated or has a bumpy texture.
If you have a mole like this, your primary care doctor
should take a look at it and may perform a biopsy.