The main cause of nail pops in drywall is a change in the moisture content of the wood studs to which they are secured. Less common is the case where they are pushed out by movement. The pops occur on many new homes, sometimes before the home is occuppied. Waiting for some time before fixing has the advantage of letting other pops of nails show their heads, thus grouping into the same fix. Nails are more prone to pop than drywall screws but the popping happens to both forms of attachment.
The head of the nail that has begun to rise through the painted surface can be hard to detect,
with such a fine crack line presenting itself before the head bursts through.
If you have one or a couple nail pops, chances are strong that more are to follow suit. Check the stud lines to find them.
1) To repair the pops, the nail will either need to be pulled and replaced with a drywall screw, or the head should be countersunk with a hammer and nail set. You might need to add screws or nails to pull in the board if it was never properly fastened. (the nail tapped back-in may reappear)
2) Use spackling paste or compound to fill in the hole and taper off the patch.
3) Lightly sand and re-apply the patch. Complete the sanding and then paint to match the surrounding color. It may help to wipe the surround texture with a damp clean rag, to both blend and serve to contain the repair area.
If the paint has a sheen, sealing the patch before painting can help ensure a sheen match.
Screws that have lift back through the surface should be either turned back in or replaced with deeper screws if too shallow a screw was set.
Other Patching and Repair