So I have a team powers 2s 6800mah 70c lipo battery that I bought last year and have probably less than 50 runs. I own two and treat both the same, but one decided to puff a bit. It is not puffy where its really obvious unless you look at the battery and notice both sides are uneven. I have never over discharge or overcharged. It is one expensive battery so I don't want to put it down, but nor do I wanna burn down my house.

I'm trying to find out what the reason is for this slight puffiness and if its still worth using. The cells are at their normal storage voltage with 3.7v and 3.8v.

Any help would be great.