Can't locate the opening of my fistula. How did you?

I thought at the beginning that my fistula is in the same place where an abcess was 3 years ago. I always have pain in my left side. However, all the drainage is on the right side. So, what causes the pain on the left side: fissures or what?
What cream do you use? I read that sudocrem is the best for fistulas.