Neo Air Repair?

You can put weigh on the mat and listen in a quite place. You can take a spray bottle with mild soap and spray and look for bubbles. I take mine into a pool and submerge quickly and find the hole that way. I have found that with small leaks you need body wight to find them. I have dunked a mat and found nothing sometimes you have to squeeze to force air to see it. If it is a micro leak you will get micro amounts of water in the pad. Another approach is to blow smoke in and look for where it escapes.

I had to struggle to find Prolite leak, which would be same as Neo-Air

Tried water and soap but couldn't find anything

Submerged in pool, didn't see anything. It's hard to get it to stay under water. You have to push one section of mattress at a time. Pushing it underwater will also produce pressure inside forcing air out the hole. Finally, I found a stream of bubbles coming out.

I don't think you have to worry about water leaking in, the air pressure inside keeps water out.

Then, when I found approximate location, I took it out and used soapy water. A bubble formed and gradually got bigger. Then I marked where the hole was, dried it off, and patched it.

Once I had a mattress that got a leak at the seam. I don't think that would be repairable. Maybe you could heat seal with iron.

I've heard about leaks of valve area. You can buy a replacement valve which might work.

Unfortunately because I had the misfortune of owning a POE piece of crap. Best way that I found is to partially fill the pad then roll it up exposing only a small section to air. Then put it in water. Using the smaller volume will do two things. One, it allows you to get it fully submerged so you aren't fighting the pad to keep it in water. Second, you can get a higher pressure which can be the scenario that causes the leak to either appear or certainly go faster. It would come closer to duplicating the pressure that the pad has while it is being slept on. Also, if you don't have a tub you can use soapy water and the same method. Good luck

Thanks for the prompt feedback! Problem has now been fixed.