If it has some small roots it should recover. stake it to keep it steady so the roots do not get torn. Until fully rooted, the cuttings are very unstable and can rip off the new roots. It should keep going.

I had the exact smae thing happen to me with an Intense Rainbow cutting I had. I went out to the front porch and noticed that it had fallen out of the pot. It had a root before but when it fell out the root broke. However, I put it back in the pot and the leaves are continuing to grow. I think your cutting should be fine. I agree with supporting it. I did the same thing myself.
Andrew

support can be done with a combination of bamboo stakes with plastic tape tie and styrofoam pieces as shown:
{{gwi:1187257}}

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I once accidentally broke off a branch from one of my potted plumerias. It fell in my greenhouse and I forgot about it because I had a lot of other plants to move. I found it about a month later looking great. I cant remember if it had any roots but it had full grown leaves. When I was taking it out of the greenhouse it did not have any leaves on it and it it did not get any water! These plants have an incredible will to live.