Green laser is dimmer and battery issue

Hi, guys. I bought a cheap green laser last few weeks ago. The green laser was fairly bright at first but it has been somewhat dimmer since my 16340 battery was completely drained for the first time and also fully charged for the first time.
The laser is no longer as bright as it used to be at first.

Besides, the bottom part of my battery is slightly punctured due to the battery spring or coil. May I know is it still safe to be used?

Thank You.