Can tattoo discoloration really be due to skin tone?

I'm in the process of getting a tattoo and have been experiencing some odd rough patches and discoloration of the healed tattoo. The artist says this is probably due to my skin tone but this seems dubious to me. I've had previous tattoos using green and blue ink without this type of problem. Also, the discoloration is splotchy and makes the ink take on a slightly more brown version of the original color. Wouldn't skin tone affect the tattoo in an overall way, making it appear maybe less bright, instead of splotches? Most of the discoloration has taken place where the skin became rough and shiny and some of these rough patches have not smoothed out even after months. Has anyone experienced this? Very confused and looking for second opinions.