I Have Had New Dentures Since February. In October I

I have had new dentures since February. In October I got my permanent. My last dentist appointment was Mid November. I recently noticed 4 small black dots on my bottom gums. My bottom plate fits less and less everyday, I mean to get them adjusted but cannot find the time. My question is.. Are the dots from the plate rubbing or is it cancer? I'm very worried and since its Sunday I will not be able to get in until an available appointment.. Which could be many days.