For an art project I'm using a small propane torch in a tiny windowless room. I use the torch for only 5-10 minutes at a time, 3 times in 90 minutes. The torch actually heats the room, and there's a scent (not propane gas smell) and kind of a stinging in my nose. What are the by-product gases produced when I use the torch and are they harmful?

It would help to know what you're melting/bending/heating with the torch.

I'm passing the flame over poured resin to release the bubbles and get a smooth, clear coating. The resin is not flammable; it's the kind you use on bar-tops, table-tops, etc. Thanks.

Probably the fumes from that is where you are having problems. I am sure that is not good for you. You might want to reconsider doing this somewhere with ventilation.