Help! Single black spot on fish’s cheek

[Spydersweb]

Hello, I’m wondering if someone could help me. So I’m doing the tank transfer method for my fish because I’m 99% sure that it got into my saltwater tank. I know it wasn’t velvet, and I know it wasn’t Brook, And they were white spots. I did a freshwater dip and didn’t see anything. This is the first transfer during the TTM, And I noticed that my Thang has a big black circle on his cheek. I’m trying to find out what it is, and how I should treat it. It just appeared overnight. Can anyone help me?

 

[Daniel@R2R Verified Admin]

Hey how's he doing?

 

[Dr. Reef Verified Sponsor]

pic is a bit too small and blurry and from a distance where i cant make out. Anyway to post a bit closeup pic of the fish and spot