Hello- It is important to pre-test an area prior to using any type of fading cream, as irritation, allergic reactions, and/or you may experience undesirable affects or reactions from the cream. many of the fading creams on the market do warn of such side-effects and reactions which may occur with the use of these creams. When using this product: Mild irritation may occur. I would suggest that you discontinue any further use and consult your physician - if: A gradual blue black darkening of the skin occurs. Irritation becomes severe, or if you start to experience any other unusual reactions or conditions. Also- the use of fading creams aren't recommended for use while taking birth control, and certain medications may also have a negative reaction. It is also advised to stay out of any direct sunlight. I would recommend that you make an appointment to see your physician if you notice any worsening in the discoloration of your skin. If you have any further question's or concerns, please don't hesitate to ask!Thanks,Carole N.P.Please rate my answer, so that I may be credited for my work! Thank You for using Just Answer!