Sick Bangaii Cardinal

[MarineEddy]

I have a Bangaii Cardinal and today when I was feeding I noticed a white lump on it's side. It looks a bit like a small wart. The fish is still behaving the same but I just don't know what to do about it. If anyone has any ideas could they also tell me a cure? I've also attached some photos. The quality is awful but you can still make out the lump.
Thanks in advance,

 

[Bkmrsteel]

I can't see the pick, but dose it look like he ran into a rock?

 

[MarineEddy]

I don't know, if he ran into a rock would it be a lump? I thought it would be a cut if it was that. Thanks for the quick reply