Mistake???

I received a pt on 3-11 that was admitted on dayshift the day before. During my inital assessments I noticed that the pt had some reddening that blanched when touched. the pt was semiconcius and obese. So i order protective barrier and repositioned him every 2 hours and placed pillows where they were needed with proper documentation. The pt's buttocks were no longer red at the end of my shift.

Two days later when I came in to work I recieved a call form the supervisor saying that I did not care properly for this patient. They found a reddened area the day before on the patient's heel. I informed them that I did not see any redden area on the heel when I had the pt TWO days prior to that. But that I did see some on his buttocks but that it was blanchable and went away once repositioned. The supervisor said that I should have taken a picture of reddened buttocks for the chart. I thought we were only supposed to do that when it was a stageable pressure ulcer.

The supervisor then said that I did not assess thourghly enough if I did not see the reddened heel. I know I looked at the pts feet because I put teds on during my shift. I checked my charting and noticed that the prior and post nurse did not document any reddness on the heels either. The supervisor said it was my responsibility to take the picture but I don't understand why since it was not reddened on my shift. When I asked if the supervisor asked the other nurses that took care of the pt, he said they had nothing to do with it.

Now the supervisor said that the next time this happens I'll be written up. I don't think I did anything wrong though. I can't docuement on something that wasn't there.

What would you do in this situation?