Hole in the head, wound or something else?

[craig and fish]

Our betta recently developed this grey patch on his head. It's not white and feathery like a fungus, and it's basically flat with the rest of his body, not recessed like a hole. It's like a slate grey patch with no scales. His water was quite high in nitrates because of overfeeding so I've changed 20% per day for the last 4 days, and cut back to feeding 1x per day with less food. I used betta fix for the last two days. Also vacuumed the gravel each of the last two days. No improvement or worsening so far.

He also has significant swelling of the abdomen, which appears to be constipation, as his scales aren't 'pineconing'. I was thinking this was a separate problem, also derived from him eating the flakes meant for the other fish, which caused the overfeeding.

Looking at the zoomed-in pictures, I also noticed he has developed fin rot. Could the fin-rot be the same thing on his head?

He still eats fine, although he has gotten more aggressive with the other fish he lives with.

I'm at a loss for what treatment to pursue, because I don't really know what this is, hole in the head seemed the closest from the pictures I've seen on line. I included two pictures for comparison, it's just a smooth grey spot as in the photos. Can anyone help diagnose this? Should I just give him a wide range anti-biotic for the fin rot and focus on keeping the water clean? Thank you.

[LittleFish2012]

I agree that feeding him the wrong food is causing him to be "overweight" by a fish's standards. Try feeding him pellets meant for bettas instead of flakes.
Not sure what that is. It reminds me a little of my fish. He's got "grayish" patches on his head and around his face too, but thats just how he is. He is not affected by it.
For the fin rot, yes. Definitely give him a wide range antibiotic along with keeping his water clean. Raise his temp to at least 74 degrees F if you can. That'll clear him right up.
If he's in a filtered tank, be sure to take out the filter cartridge when medicating him. Otherwise the medicine won't circulate.
Keep an eye on him and watch for anything that may be amiss.
It's also possible that the grey patch could be nothing. You just don't know with these fish. :/
I hope that helped a little bit.

[craig and fish]

Appreciate the reply. We've got him in a hospital tank at about 78 degrees and are two days into administering Jungle brand Lifeguard treatment now. The gray patch seems to be clearing up. The fin rot looks to be improving, but I'll have to take new pictures so I can magnify and see it up close to be sure. The swelling in the mid-section is still there. He won't eat the peas we've prepared him, so we'll be trying some salt as recommended on many sites once we're done administering the medicine. Thanks again. Craig.