You could also make notes in the note section about it so you can have a reminder of what happened.
If you look at my chart, my temps take quite a few dives

I too am hoping I am not doing something wrong (I got off BCP in April and am still stabilizing, I think) so next cycle I will be switching to vaginal temping because my oral temps seem to be more inconsistant. For the past 5 days or so I've been temping both orally and vaginally, writing down my vaginal temps in the notes section while still charting with orals for this cycle, and they seem to be a lot less see-saw-y...