Drywall – Horizontal lines bulging on drywall

A few additions to Jeff's advice if you decide to replace the damaged drywall.

1. I'd suggest you look into waterproof drywall or mold resistant drywall. There are various products that do a better job than the typical green board that you would use in the bathroom that will help if you are installing in an area that has a lot of exposure to the elements.

2. Double check the thickness of your drywall if you are patching. If you replace a 5/8" with 1/2", you'll notice it.

3. Use screws, especially on the ceiling. They take more time, but hold better and are less likely to cause the nail pops that you are seeing.

That being said, I think it's entirely possible that you're just more aware of drywall issues and there may not be anything wrong. To know for sure, I'd go up to the attic, pull up the insulation where you suspect damage, and look for water rings or other mold growth. Use a flashlight, no need to feel with your hands (and risk falling through). While you're there, check the insulation for blackening that would indicate mold is growing there, and if so, replace any damaged pieces.

Your ability to see the joints between the drywall is just a sign of not enough paint and/or primer. And popped nail heads are normal as a home moves. My personal plan is to replace all the popped nails with screws and double up on the spacing the next time I paint to minimize this issue.

The most likely reason for you feeling worse is leftover dust from the work performed. That will include dust from the drywall, from sanding the filling and especially mold particles from the disturbed wall. The room may look clean, but replacing drywall will produce a lot of tiny dust particles that will settle everywhere and make an allergic person feel really bad until the dust is removed.

It might also be allergy to the new paint components and if that's the case then the paint has dried by this moment and you'll feel better.

So the number one thing is to clean the room thoroughly - wipe everything where the dust and mold particles may have settled at least twice.

As to painting over. Latex paint will form soft yet rather strong film that will bond and contain the mold for a while. If there's any amount of humidity and mold is indeed in the wall then mold will continue to grow and will likely resurface at some moment. However until that happens you can feel more or less safe - the dried paint is like soft plastic covering and containing everything.