Hi XXXXXXX,

The condition you are describing sounds like "koilonychia", which causes the nail to flatten out and appear "spoon-like" in some cases. This can be caused by iron deficiency anemia, or by working conditions where the hands are subjected to chemicals, oils or soaps that soften the nail plate and cause it to turn upwards.

If it is caused by exposure to such chemicals, the only way to correct it is to stop the exposure and allow the nail to return to normal. So, he doesn't need to soak it in anything. He might consider using protective gloves when he is working.

The other thought is, he might want to see his doctor for some blood work to make sure his blood count is OK. Most likely it is whatever working materials he is subjecting his hands to. So, either protecting his hands or when the wall is completed, the nail will gradually return to its normal shape.

If the condition worsens, pain increases, or he develops other symptoms he should see his doctor about a possible nail infection.

Hi XXXXXXX,

Because it is only one nail, it is probably a combination of exposure to some chemical plus injury to the nail bed. Building a rock wall, I would imagine repetitive trauma to one's fingers happens frequently. He may lose the nail if it is severely damaged, in which case a new nail will regrow. He could probably protect it further by wrapping the nail up with some tape to support it, and this may keep it from causing pain (not too tight). Keeping it trimmed as it grows out will help also. It's hard to say if will just fall off, or have to grow out.