If I don't pick up the heart container while leaving a dungeon, can I still get it?
Solution 1:
According to this post, if you miss a heart container after completing a dungeon, the container will appear outside the dungeon entrance for you to teleport back to.
No, it will appear outside of the dungeon when you teleport back to it.
If you look at the link, all 3 posters agreed that this is what happens.
I also found one other post where someone mentioned this as well.