I haven't played Pizzicato in a year, what can I do for my callouses?

I play the Cello in my school's Band (we don't have an orchestra) and during marching season I was on drumline, then I didn't play for a semester. I just started playing again and I'm getting a really bad sore on my index finger, but I have to play Pizzicato during our Jazz song. What can I do to keep the pain away but still strengthen the skin on my finger so it won't hurt anymore? I've considered using a bandaid but that'll just make it hurt more once I take it off.