I got a little Dracaena plant a few days ago. I took it with me to work this morning for my office window, and by the time I got there, I noticed a lot of small black dots/patches on the leaves that I'm pretty sure were not there this morning. I walk to work and it takes me around 20 minutes, it was really cold outside (-10 Celsius). I had the plant in a bag but I think the cold may be the cause of the spots. Any ideas whether this is the case? And is my plant going to be okay?