Hi and welcome to the forum
What other fish are in the tank and which fish attacked the angel?
Has the angel lost an eye?
The best things to do to help fish heal is keep the water clean and feed them a varied diet.
1) Do a 75% water change each day to help reduce the number of disease organisms in the water.
2) Keep the temperature at a suitable level for the fish, around 26-28C for angelfish.
3) Make sure there is plenty of aeration/ surface turbulence to maximise the oxygen levels in the water.
4) Feed the fish 3-5 times a day with a variety of dry, frozen (but defrosted) and live foods.
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Monitor the wounds for infection. This will show up as red areas around or in the wound, or white fluffy stuff. If the wounds get infected, then add a broad spectrum medication that treats bacteria and fungal infections. But do not add medications unless the wounds become infected.
If you have to treat the fish, use Methylene Blue or Triple Sulpha. They both treat bacteria and fungus and are safer than most other medications. But monitor the fish first and only treat if the wounds become infected.