Damaged dendrobium

[Arachnida]

Hey everyone. I attended my first orchid fair on the weekend and it was amazing, but so crowded! And in my rush to quickly buy an orchid I wanted, I must not have checked it thoroughly enough and have this morning noticed that there was a wet spot on the stem of the new growth. I peeled off the wet outer sheath (which was coming off anyway) and it has a mark on it which looks like it's been infected. I poured hydrogen peroxide on it and placed it in front of a fan to see what it's like when it's dry. The stem isn't soft yet, but it is light brown around the cut. Should I remove the new growth now and stop it from spreading to the main stem? Or is there something I can do to fix it?

[rbarata]

I'm not an expert but it seems the plant has vigorous roots which is a good sign. Under the brown spot, the stem is dying so I woud cut off the entire new growth.

[estación seca]

First, is there any way you can get a refund from the seller? This plant is unlikely to survive, and you deserve to buy a plant in good health. If you contact the vendor (name should be on the tag) or the sponsor of the fair, and send this photo, they should refund your money or replace your plant.

Right now, get a sharp knife or small scissors. Making only one cut, remove the entire new growth from the rest of the plant, as close to the previous growth as possible.

If you see any discoloration of the cut surface on the older part of the plant, the infection might have spread already. In this case it is unlikely you will save the plant. Sterlize your cutting tool in a 10% solution of household bleach for 5-10 minutes after each cut. Keep cutting until you are into completely healthy tissue. The plant is so small that, if the infection has already spread from the new growth into the rest, I don't think you'll be able to save it.

Once done cutting, put some powdered fungicide, cinnamon or sulfur on the cut surface, but not the rest of the plant. Hydrogen peroxide kills organisms on the plant, but not inside, and your plant has an infection in the stem. Let the plant dry for a day in the shade. Repot it and water it. Let it get dry before watering again.

If the plant survives, the older part will push a new growth.

[Arachnida]

Thank you both for your replies. I will contact the seller with a photo and cut off the new growth and see if the infection has spread, and then put cinnamon on the cut. It is a young plant so if it has spread I don't think it will live, but hopefully the seller can either refund or replace it.
Thanks again guys I really appreciate it