Strange dark brown spot on bottom of foot

Strange dark brown spot on bottom of foot. I have recently stopped medication and began the Atkin's Diet for the reason of an over growth of yeast.  During the process of induction, a smooth, black to dark brown spot showed up on the bottom of my foot toward the middle outside.  It looks like a perfect smooth cigar burn about the size of a quarter.  Could this be some kind of cleansing effect from the Liver?  It kind of looks like I soaked up ink in my skin but have not.  It has been 6 weeks not since beginning the diet.  I feel wonderful but the spot has me worried.  It hasn't faded one bit in 5 weeks.

[Vanessa Lacuesta]

Hi

This hyperpigmented spot sounds like a mole. This does not seem to be a side effect of the liver medications. Continue to observe the spot. Note the ABCD of mole character. Note for appearance, borders, color and the size of the spot. Any changes in color , increase in size and any irregularity of the borders should raise suspicion. If these are present, a skin biopsy may be indicated, this may offer some form of discomfort for some time as the spot is located underneath the foot.