+1
This is very helpful in more ways than you can imagine. Even more useful than a mirror sometimes. One time I had a problem in my toe (under the toenail) and at the same time, I was suffering from a problem in my hip (not to mention a big belly). It wasn't easy to bend and see the toe problem clearly. So, I took a few close up pictures with the cell phone camera and examined them before putting some ointment.

A camera is also very good for "preventive measures" that will help you NOT to need first aid in the first place. One day I was looking for some items and thought they might be on top of a cupboard. Due to my health problems (knee, hip ..etc. ) I avoid using tall ladders. So I used a short ladder to almost reach the top of the cupboard and photographed the blind area instead of climbing higher to see with my own eyes.

This is not exactly "first aid", it is "accident prevention" which is also important.