I would say that black cover, being made of glossy black tape cause a lot of heat to build up right there at the stem and has caused it to rot. It looks pretty bad, I don't know if you will be able to save it. Really depends on how deep the damage goes into the flesh of the stem, given that it is "bleeding" is not a good sign. If you have some tephlon tape, you could try lightly wrapping it to seal the wound, or get some clean wax and get it warm enough and flatten it out real thin, then wrap the stem with that, making sure that the wax "band aid" goes 1-2cm above and below the wound. Press it just tight enough to make it hold. There is also a pruning spray that you can get from the local hydro shop or plant stores that you can spray onto the stem to seal it. That is what I use for any breakage and it works quite well

unfortunately I can't remember the name of it. Hope this helps, and hope she survives
