It's nothing to be concerned about. The stinging and burning will subside but it may day a day or so. Your sphincter muscles naturally tighten around the catheter when you remove it creating more friction. The best way to remove a catheter is relax as much as you can. When the catheter begins to come out try to pee. This will help relax your sphincter and eliminate any discomfort during or after removal. The type of catheter also makes a difference. Some 100% silicone catheters hurt like hell when you remove them because the eyelets have a sharp edge on them. The best ones are silicone coated latex. The eyelets are much smoother.What size did you use? You should have started with a 12 or 14fr, nothing larger.Don't give up. The more you use catheters the better they feel.