Betta head injury

[Vrykolakas]

Hi my betta has this odd marking on his head im not sure what it is ive noticed it only a few days ago it seems like its gotten worse if anyone has any ideas what it could be i appreciate that alot.

 

[betta4ever!]

Hi!! Could you answer some questions?
How many gallons is your tank? Is it cycled? What temperature is your tank? Does it have a filter?
Does it have a heater?What food brand do you use? How often do you feed your Betta? How much? Water parameters? Before your Betta became ill how often did you perform a water change? What percentage of water did you change?
From what I can see, he somehow got hurt. A photo of the tank would help...