[Espeefan]

No juice at all? If the bad cell really does read super low, I wouldn't try to revive it. It went bad for a reason. Likely an internal short that drained it. I would be leery of trying to charge it, or run it under a load, even if it can be recovered. It's not really worth the collateral damage it could do. A bad cell that is revived is likely going to be quite unstable.

Out of curiosity, was the battery in storage for a long time? It's suggested to store LiPos at 50 or 60% capacity, or no less than 3.7 volts per cell. Best to check their voltage levels at least once a month to see how balanced they are, or even cycle them.