It honestly looks like it has little damage so you could probably safely use it, but what I do when my batteries get damaged is use them for charging other batteries, powering goggles and other stuff. Just smell the battery and if it is a sweetish smell, throw it away, but if not, charge it on a low c rate and only charge to 4.1v.
Or you could remove those two cells and make it a 4s battery, I did it once and it worked well. Just be careful!