Forgive me if this has been answered...

[Laura in VA]

but how does a neg rep disappear? I had a neg rep point earlier, but now it is not there, and the other reps are (so it's not an issue of it being there, but just not being in the last 5). Thanks!

[Plaid Dad]

If you received more rep in the interim, it may just not be visible since only 5 reps at a time show up. It may also be that the moderators removed it if they felt it was inappropriate.

[Laura in VA]

The reps before it and after it are showing, so I don't believe it's a case of it just moving down. Hmm...

[Jenny in Atl]

Most likely one of the moderators removed it for being unfounded.