Once they "puff" they are not long for this world. They will continue for a few more charges, and then they will deterioriate in their storage capability. I have found that the cell that has "puffed" is bad, and the discharge voltage is going to be lower than the remainder. I have replaced the offending cells with other cells (the good ones) from other "like" size batteries that have also "puffed" and continued for many more charges.
Short of replacing the offending cell, life is short for that battery.
Paul Walker