Antique jewelery box

I made this for my mother in law, she loves antiques. I found a picture of one in an auctions and made it into cake! I had some issues with this one. I don't know if it was the humidity or the fondant, I used duff for this, and have never used it before. The cake started to get condensation on it all over as I was decorating it. It made it really hard to paint onto it. And had a bit of damage to the one side. I have never had something like this happen before. Also, the gold never goes as well as I would like, any suggestions? I used luster dust and one that comes as paint. TFL