I felt some acute pain while walking for a half-year or so. It was increasing over that time, so I went to the doctor. Doctor said it was a papilloma wart under the sole skin, so she cut off the skin with some milling cutter(no Idea what it is called in English) and then pour some acid (even the smoke was obviously visible!) into the wound. It was painful, but FAR from how I expected it to be.
Then why did my old doctor do it all at once. Also I asked my GP if it was a scam as I used to get it done in one shot. He agreed there was no need to go many times.