so according to the cutscene's room in damia's temple there's an secret room in the abanndoned temple. where is it?
by abandoned temple, do you mean the first temple or the plant infested one?
If it's the later, their is a room near the begining of the temple that leads into a dead-end.
If you have enough weight on you (aka corrupted seeds) you can break though a tile in the floor, which will play an event afterwards.
Hoped that helps you