Betta Fish: HELP! My imbellis scratches himself so much, it’s breaking skin

I just came home and saw this big spot on one of my imbellis' head. At first I couldn't understand what it was and thought it might have been from a fight (there is another male in the tank, but they rarely get in contact, and when they do, it's very quick). But there is no other sign of fighting, no ripped fins or anything.

I gave some food, he ate normally and was acting normal until he started scratching himself repeatedly! Then I realized that he might have been doing this so often that he must have started breaking skin from it.

Yesterday I put some catappa leaves in the tank. It's from a brand and a bag I have used before in tank, so nothing out of the ordinary, but this is the only thing I can think of? What do you guys think? What can I do?

All other fish and shrimp in the tank look fine.

As I'm writing, he has just layed on the bottom… never saw him doing that.

I'm posting some extra pictures in the comments.