What Causes Intense Burning Sensation Below The Waist?

Had a nonsurgical ablation done in an EP lab yesterday. During the procedure I had an intense burning on my left side below waist. I complained during the procedure and after it was over the nurses were taking the leeds off and one of them said the area was red. But looking at it today it is clearly a burn. what would cause this? I have some pain in the area but it looks like it is healing.