You shouldn't need to stand right in the thick of the haunting to place the candle. It's been awhile since I played
The Room, but I remember that most if not all of my hauntings could be cleansed without taking proximity damage. Perhaps you're actually standing too close to see the correct spot to place the candle. In the area of the haunting, you should of course try the floor and every available surface (tables, windowsills, counter tops).
There's a thread in the Quicklinks that deals with holy candles and saint medallions
here. You can continue that discussion if you like; I'm sure someone else will have this problem later, and it would be nice if they could find answers to your question there in the Quicklinks.