I had to take about 60 pics to get these 2 that showed this accurately.  They are full-res pics so you can see it.  There appears to be a lesion of some kind that is about half the diameter of a penny, just under the skin, you can see the discoloration.  Protruding from this is a white pustule of some sort.  I can't tell if this is damage from running in to something, or if this is the dreaded "I-word".

So you can see in the pic without the flash, it looks white.  This is how it looks under normal light.

The pic with the flash makes it look dark.

The only thing I have done different is that I put a canister filter on the tank and cleaned the glass really good, then pulled a dead coral colony, moved some rock, moved some corals, and left the canister running for 2 days.

I suppose he could have freaked out and bumped into something, or something could have just gotten 'caught' on his skin.  He's eating fine and otherwise up front and personal.

IMO, I would say it is not Ich. In the 2nd pic Bud, it looks like there is more soft tissue involvement which encircles the white spot. He very well could have bumped into something and lost a scale or two and bruised the soft tissue. As long as he's eating, acting alright, etc., I would just keep a close watch on that area and him. If it is a problem, his natural immune system may take care of it. If not, and if it's not Ich, you may want to treat for a bacterial infection. As an FYI, Melafix and Pimafix can be used directly in a reef without harm to corals...I've used them both (some corals ay close for awhile shortly after dosing but they will open up fairly soon afterwards. Good luck!

I should also mention that there is actually something protruding out of that spot, about 2mm. Like one of those pesky tube worms that pokes into your fingers when you grab a big old rock in the tank.

Anything you are aware of in the tank that could stick him? Some kind of barb thats stuck in there and basically infected?

The protrusion is gone today, the spot is still there...keeping an eye on him...

Is there another tang in the tank that could have used there surgeon like spike at base of tail to get it? They will often swipe at each other if so maybe he got a little to close. Also if you have ich it likes to be around base of tail and in the fins first. This is not always true, but it was what I read was in most cases.

glad to see there is some improvement.

Seems to have been just an abrasion. It's pretty much gone. Thankfully!!