Li-Po Question-- Fine? Bad?

[BL_RV0]

Ok, so I just received my used Protek 3s 4000 pack for my Stampede. I charged it up, ran for about 20min, came inside, and felt the pack. It felt sightly soft, but not soft-soft like puffed MaxAmps soft, but I could push down the shrinkwrap anout .5mm on either side. Is this a puffed LiPo or just a loose shrinkwrap job? Keep in mind, the pack does have another layer of clear shrink over the factory wrap. Another question-- is it okay to charge my LiPo's while I can watch them, and then once they are done, go take a shower or eat breakfast or something like that? Span of time from my leave to my return would be ~15min. Is it okay to leave a LiPo to sit for that time fully charged?