After killing spider boss

[asprah]

I just killed spider too, and I also can´t get in that area again, so I am pretty sure there is no way to do that after you accept reward. Don´t worry though, nothing special inside to collect, I think I only found 1 magic crystal- that´s about it.
If you really want to explore it just load the game?

[harm44]

thanks

[Ryastar]

Yeah, you can't get back in after you kill the boss. I tried during my first game (i did the same thing you did), but no dice.