@Elissiaro Been following your work here, quite impressed and nice maps, even before starting to fix things up. So great job on your maps
:D
That said, when it comes to lighting, some might disagree with me here, but I think it comes down the the atmosphere and feeling you wanna build in the cave. This can be affected by key factors as lighting, audio and effects (like adding fog). Personally, I like the lighting in the cave, as it puts the focus on the player, and lowers the sight around you. This is both realistic and can work as an advantage depending on how you use it in story telling and gameplay.
If your worried about it being too dark, you could add a little lantern that has a glow around the character, while still having the area in the distance dimly lit.