Puffed up a "little" covers a lot of ground!
If the Lipo is a small inexpensive one, I'd likely dispose of it, rather than risk an expensive model.
On the other hand, some of the "cheap" small lipos seem to be prone to doing this, and while it's an indication
of possible problems, seem to continue to function. Perhaps not as well or long, but adequately.
It's the old risk/reward bit.
I and others have used "lightly" puffed lipos without problems. Most of the time, we get away with it.
Occasionally, the results may be spectacular!