Emperor Tetra parasite?

[triivk]

Tetra was previously injured at the site of potential infection, it was a minor red rash before this development. I am unsure on what it is/and how to treat it.

I would really appreciate any information on what it may be/what to do, thank you.

 

[Autumnsky]

It' is hard for me to tell. Is it a damaged area inside the black strip where the little black rays are coming up? Is it a hole there, or does it look like it is healing?

Maybe this could help figure out what it is.
https://www.aquariumadvice.com/fish-disease-index-for-diagnosis-and-treatment/