While I was on vacation my dog had an accident on the carpet. The people who were watching her did not notice the urine. When I got home, 2 weeks later, I noticed it. I removed the furniture from the room, pretreated the area and then steam cleaned the entire room. Now the smell keeps coming back when the humidity is high. The stain is gone, but the smell is still there. What can I do to take the smell out of the carpet?