I've had a dark mole on my foot for 6 months and has changed a few times. what could it be?

Mole on foot: The worst thing this could be is a melanoma. Changing moles especially on the foot need to be examined. Please get this checked out immediately. I feel that moles on the foot and changing moles especially need to be removed.

Any dark mole: that increases in size is suspicious for melanoma. Show it to your doctor for accurate assessment regarding need for biopsy.

Difficult to tell: It is tough to tell just from your description exactly what this spot could be due to. The possibilities include a nevus (benign mole), liver spot, or, in rare cases, malignant melanoma (cancer). You should have your primary doctor or dermatologist actually take a look to better determine the diagnosis. It is always wise to have a mole that changes checked out. Best wishes.

Moles: Are usually benign. But sounds like this one is changing see your doctor for an eval. Make sure all is ok