You can review which days you have already entered data for by using the timeline at the bottom of the motif screen.
1) From the homescreen, press Track Symptoms
2) Press on the timeline at the bottom of the screen
3) Scroll down to see a list of days that data has been entered for
4) Press on a specific day to see a list of the motif segments scored
5) Press on a specific entry to either edit the score or delete it
6) Press close at the top of the screen to return to the motif
You can also watch a video on how to do this here