The data is a “serialized object” in PHP. You’ll see something like “s:10” – that’s string, length 10. So if you edit the description you would also need to change the length. You might be able to recover it if that’s the problem.
If that doesn’t help – and you don’t have any backup – then email me the object and try to tell me exactly what changed. I’ll see if I can recover it for you.