Trust me you will know when you have one. You don't need to look with a mirror. They are painful buggers and take a long time to heal. As soon as you notice one get all pressure off that area immediately. Lay down, sit weird, don't wear any underwear- whatever it takes. Sit baths help. Do not try and squeeze it. Take it from me on that. Unless you want to be maimed for life. I got a topper for my bed at Costco that is made out of that squeeshy foam stuff (I can't remember the name right now). You know what I'm talking about the expensive, good mattress 's all have it now. It was only 120 bucks and has been a life saver. They sell pillows and cushions made out of it too. This helps a lot. Also I used to work for a company that sold sheepskins to people who were in wheelchairs. They all claimed this was a life saver for pressure sores. I bought one of the rugs and lay on it and it has helped a lot too. Company is called ruff tuff products.