“I have small bumps on my hands and feet?”

I get these small bumps with whiteheads on my hands and feet and complete random times. Sometimes they last a couple days some times a couple weeks. I seen a doctor back in February that told me he believed it to be a form of athletes foot but I just don't know if I believe that is what it is. I also read online it could come from having metal in your body. I have a titanium rod in my pinky on my right hand from cutting my finger off when I was 6 years old. I am now 37. I don't take any medication. Could you please tell me what this could be from? It is extremely annoying and it itches and if I pop them then my hands kind of burn and it seems like if any of the puss gets on my skin I get another breakout of them again even worse.