I think i messed up?

Okay after doing waterfall quest i dropped the amulet and the pebble thingy. Then i got a slayer quest of about 127 fire giants which the waterfall is the best place to kill them right? Well here is my question… is there any way i can get back into the waterfall?

yes you just get the amulet again

Lol, to be a bit more specific, go back to place where you first got the ammy and talk to that guy that you freed. He’ll give to back to you, saying it ended up down there for some reason…

~ ewok

You can always go to the karamja dungeon fire giants.