POE2 Stuck In The Boss' Arena

I was doing Steaming Springs and I cleared less than 1/4th of the map and ended up entering the Boss arena and killed it. After picking up the loot I noticed the entrance still had it's label "Arena" up (instead of no sign and an open entrance) and it wouldn't let me back into the monster area. I opened a portal to town and re-entered but ended up at the same location. I changed characters and entered a portal and was still in the sealed area.