If you lose your memory, can you get it back by having others reenact how you lost it in the first place?

Answer 1

If you're talking about a traumatic event that you don't remember, then re-enactment may help, but as the other answerer said, it could produce false memories. But as for others re-enacting, that probably won't help as much as YOU re-enacting what happened, perhaps with other people's help.
Another trick is to go to the actual location where it happened at the same time of day that it happened, do an activity that you were doing immediately before (including put on the same clothes), and so on. These are associative cues, and may trigger nearby memories of the event that is lost. Recreating smells would be ideal, which is another reason to use the actual location. There may be smell memory-triggers that you didn't even notice.

Answer 2

When you lose your memory (i.e. forget), generally you don't remember how you lost it; it just goes. However, if you're talking about a traumatic moment or an eyewitness testimony, that's a different issue. The only way others would be able to re-enact it is if the others were there or knew exactly what happened. BUT this could lead to a false memory, where the mind of the person is biased by what he/she sees in the re-enactment. The bias is due to social influence and suggestion. This has been shown in cognitive neuroscience and psychology to easily occur.

If, though, the enactment is 100% identical to the actual event, it is possible, though not certain, that one could get the memory back. BUT that would take a lot of effort, and you would never know the accuracy of the memory (whether it's a suggested or real memory).