What Causes Darkness Around The Cuticles?

I have recently noticed the cuticles on my fingers are dark and increasing up my nails. I have otherwise healthy hands and fingernails. I am curious if some of the many meds I take could be the cause or if it could be something I need to see my doctor about. I live on less than $400 a month. I would not have wasted my time if it was more clear I would have to pay to get help. Sorry to have wasted your time.