Is this hole in head or injury?

My Betts is in a 10g planted cycled 0/0/0 with 2 adf, shrimp, and a platy. went to feed him today and he had missing scales on his head. He seems active still and ate I'm just concerned as to why this happened does it look like hole in head or an injury. What should I do to prevent infection or further injury

It doesn't look like hole in the head. It's either an injury or a lesion of some sort.

On this photo it looks like an injury, if so keep the water clean and it should heal just fine.
Just keep an eye on it to see if it expands or get covered with a fluffy looking growth.

Bettas have a reputation for trying to squeeze into gaps which are too small for them resulting in missing scales like this. Does any of the decor have small holes he could have tried to get through?