Please post in the correct place. There is a sub-forum specifically for Battery questions, and that is where this should have been posted.
Your cell may be recoverable, but that depends on how long it has been sitting at that voltage - the longer it has been, the more damage it will have suffered, and the more likely it will be to overheat when you try to charge it, especially if you don't use the appropriate charging rate.
When fully charged, it should read 4.20V.
Moving this thread to the Batteries section.