weird spot/cut on flame angel need identification

[reef chicken]

i bought this flame angel about a month ago he has been doing great. the other day i noticed this weird spot that almost looked like a cut or something. injave recently added a talbots damsel and the flame really did not like it at first but things have called down now. he was chasing the damsel a lot a thought possibly could have cut himself on the rocks. i have seen zero aggression by the damsel and watch my tank closely. any idea on what this could be? the flame is still eating great and behaving perfectly normal.

 

[vetteguy53081]

i bought this flame angel about a month ago he has been doing great. the other day i noticed this weird spot that almost looked like a cut or something. injave recently added a talbots damsel and the flame really did not like it at first but things have called down now. he was chasing the damsel a lot a thought possibly could have cut himself on the rocks. i have seen zero aggression by the damsel and watch my tank closely. any idea on what this could be? the flame is still eating great and behaving perfectly normal.

This looks to be mechanical injury which often heals on its own but this one, I recommend treatment using Seachem Neoplex which is a broad spectrum treatment in a separate treatment tank