Need help to ID wound on Discus

Hi I've got a discus, it's been healthy, eating and completely normal all this time. And yesterday all of a sudden it was hiding, and upon closer inspection I saw that it's got this little wound on his head. It developed very suddenly (wasn't there in the morning, then was there in the afternoon).

My suspicion is that it just bumped it's head on something sharp (I have a lot of dragon stone in my tank) and has wounded itself. But I'm curious as to how it would've made this circular hole on its head.

I'm just hoping that it's not anything more sinister than that. Can you experts please have a look and let me know what you think, and what you would do?

Thanks!

Water quality is near perfect. It's an established one year old, 60 gallon tank and I do 40% water changes twice a week.

Looks like an injury, now with white spot. You could remove the fish and carefully hold in a wet cloth and using a cotton bud soaked in medicine, topically treat the wound. It should heal in a few days. Just be careful as not to get medicine in the eye or nasal area.