Question: I am currently using TortoiseHg (Mercurial) and accidentally committed an incorrect commit message. How do I go about editing this commit message in the repository?

Answer: 
I know this is an old post and you marked the question as answered. I was looking for the same thing recently and I found the `histedit` extension very useful. The process is explained here:

<http://knowledgestockpile.blogspot.com/2010/12/changing-commit-message-of-revision-in.html>
One hack i use if the revision i want to edit is not so old:

Let's say you're at rev 500 and you want to edit 497.

```
hg export -o rev497 497
hg export -o rev498 498
hg export -o rev499 499
hg export -o rev500 500

```

Edit rev497 file and change the message. (It's after first lines preceded by "#")

```
hg import rev497
hg import rev498
hg import rev499
hg import rev500

```