large soul core slot

Hi, I was playing with my friend and we were suppose to place large soul core into the slot in infested barrens. I still have the soul core with me.
But he did it without waiting for me, while I was loading into game. Now I have the core placed but I can't enter waterways. I can't teleport to him too.
I cannot do any missions now :( The legacy of the vaal and return to infester barrens and activate the stone altar won't work