Hear, hear. It happened to me, as well. I was new to Wikia and didn't know two people could edit pages simulteaneously.
Basically, if you edit a page and a small window poofs into existance and says someone else edited it at the same time you did, don't publish your changes. Just refresh your page or click on your username. This will forfeit your changes, thus avoiding glitches like this to happen. The servers were practically attempting to save both edits, wich is simply impossible.
As for reverting, you can click the small Arrow next to the "Edit" button. A small rectangle will say "History". From there, you can see every little thing that a specific page went through, down to its creation. Every dot, every comma, every space. For a non-Patroller, the only way to revert an edit is to "compare" two different edits and reverting it to an earlier save. In other terms, I basically "compared" yours to the previous saved version and saved the correct one, thus forfeiting yours. Patrollers can revert entire pages with one click, but that's another story.
If it ever happens again, just leave a message on my Talk Page and I'll handle it.