I've gotten a bout of gastrointestinal illness before while backpacking (vomiting and dihareaha) a day into a 3 day trip. I turned around and bailed out back to my starting trailhead. drove home, and spent the next two days in bed with fever/flu
symptoms. it can happen. Had I been further in I would
have simply slept it off in camp for a while and worked my way out as best I could. Was I *very* miserable? yes. was I in any real danger?, no, I kept myself hydrated. Probably the most dangerous thing was me driving home in that state for 3 hours on a highway in the evening.

I've turned ankles and other things that have required me
to take it easy for a few days. once bad enough I had to tape it up with duct tape and grit my teeth to walk it out, but never bad enough to completely prevent me from walking at all.

Bumps and bruises, yes, the occasional deeper cut - all managable with basic first aid, duct tape,and bandaids.