Yes, it can be done retrospectively, and I agree that it doesn't seem very fair. In my early days of caching, before I became a Premium Member, I had the same thing happen to me. It seemed absurd that I'd found the cache and logged it, but couldn't read my own log.
I can only suggest that you raise the matter in the Geocaching.com Web Site forum on Groundspeak's forums. I'm sure it's been discussed before, but it just might prompt someone to take action.
Do not go gentle into that good night.
Rage, rage against the dying of the light. (Dylan Thomas)