Just a little clarification - was the patient admitted from ER or transferred to your unit from rehab? Does your hospital have an allowed time to complete an admission assessment on your unit, say 24 hours? It's impossible for a necrotic unstageable pressure ulcer to occur from the time the patient was admitted to your unit to the time found by another nurse on the next shift (5 hours?). I wouldn't document anything you didn't see at the time you completed the admission assessment but if you are allowed a time period to complete it, I don't see a problem with adding an addendum that stated something like, ...after completing a second skin assessment, an unstageable pressure ulcer was found..., etc. It all depends on the time you're allowed to complete your admission assessments. Honesty is always the best policy when documenting, the problems happen when a nurse tries to cover up a mistake.