Has anyone out there had any side effects from using Magic Shaving cream for over 20 years?

I have noticed that my face is much darker than the rest of my body and I am seldom in the sun but have been using magic shaving cream since 1974. I don't know if the chemicals in the cream have any long term effects. I began noticing this complexion change in 1995 and though I have been using a skin lightener cream for the last 8 years, my face is still dark.