My plant got a blasted with cold air for a couple of hours (approximately 35-40° F) in late October early November. And it did not like that. I moved it away from my west facing sliding glass door and it is now across the room approximately 8ft away and gets some direct setting sun. The plant is in a 12 inch plastic pot with a drainage hole at the bottom. I put a miracle grow stick in about 4 months ago. I put some coffee grounds on top. And I've been misting it with water with a littleepsome salt dissolved in. I am getting new leaves but the also have the brown spots and look sad. They aren't real big either. The plant is very leggy. My biggest concern is the brown spots. I had a peperomia plant that got a fungus but it was about 4 feet from the Dieffenbachia. The peperomia did not survive and it took out my aloe plant and my pothos cutting as well. Any help would be greatly appreciated. Thank you for your time and help.