You can not teleport back (at least by design). Teleporter stones in your inventory are replaced by ancient pyramids when you get to the wastelands, and if you don't have one or both of them, replacements will be on the ground to the north east of where you start, by a section of ruined stone walls.
You can teleport back by hex editing a file in the save folder
, which should probably be ok for picking up loot, but I don't know if there could be issues with completing quests, etc.
The safest solution would be to revert to a save before the blessing ceremony, if available.