Inspection mirrors are available which include a strap for the convenience of people with limited grip. Skin breakdown can also occur from infection. The ischial area where you sit is at high risk because of its regular exposure to bacteria from your stool during bowel movements. It is possible for a microscopic invasion of the skin to occur, and an infection to develop beneath the surface. A pocket of pus can form which will result in skin breakdown, sometimes a significant enough area to require months for recovery.
Prevention is simple.
Keep the area very clean with good habits in your bowel program. Also pay attention to fevers or increases in spasticity, which can be indicators of infection. I got a sore in the emergency room when I was injured. They didn't turn me since they were afraid of doing damage. It needed surgery.