Not quite. I was able to injure myself severely with the knife, but not enough to cause death or near it. Even when pushed far into my chest, I was left with only the sort of wound that would require stitches.

When I used the knife I brought in, that's when I suspect I punctured a lung and began to bleed.

Fire created and sustained by Enclosure materials only burned the skin, but fire created and maintained by my own materials went very deep. Interestingly, fire created by me but maintained by Enclosure materials still behaved as Enclosure-made.

The creature that bit only punctured the skin but did not tear. I could tear my flesh.

And, of course, any Enclosure created space would not harm. Long falls and spikes, and closing walls.

It would warp reality, but it would not change the setting or revert to its original space.