Well like I said before I'm glad he is still alive.
Do you still have him in the breeder's net? Or is he now able to keep himself from sinking to the bottom?
I didn't see you create a new thread inquiring about treating ammonia burns but I did a bit of web surfing myself on the subject. What i came up with was pretty much what you presumed, time is a determining factor in treating ammonia burn. Just give the little guy time to heal. But in addition to time, make sure you continue to keep him in excellent quality water conditions, keeping the ammonia levels as low as possible. If you keep him in excellent water conditions (while he is recovering) his ability to produce his slime coat will eventually come back & he'll be as good as new.
Just keep a look out for irritated looking blotches on his skin. This can be an indicator that he may have developed a bacterial infection as a result of having his skin exposed due to the ammonia burns. If this happens then you should treat it with antibiotics. Personally I would treat it with Pimafix, since I've used it before for treating fungus & bacterial infections on my fish without issues. I'm pretty sure you'd be able to use it in this case without causing any further issues.
This is what I discovered after researching I, it's not my firsthand experience. Except for the Pimafix, which I explained I've used before myself.
Good luck & keep me posted on how the little guy makes out.