How do I replace rubber cover of my analog stick?

So I was playing SSB4 when I realized that I had worn a hole in the rubber grip on my left control stick. So i took off the rubber part and left the bare plastic. Playing without good grip isn't an option for me as I play competitively. However, I do not wish to buy a new one. I'm not quite sure on what to do; whether it'd be to get a grip, get a new analog stick, order an exact replica of the same part, or just get a new controller. I use a PDP Afterglow Pro Controller. Please help me.