Use pure sea salt (non-iodized) and not table salt, which contains extra chemicals that can irritate your piercing and dextrose (sugar) that can cause yeast infections.
Keeping this in consideration, can I use Himalayan salt instead of sea salt?
If your recipe calls for one, can you use the other? Both Himalayan salt and sea salt consist mostly of sodium chloride. This means that both are effective for giving your food the taste of salt. You can use either one in place of the other if all you want is the flavor.
Correspondingly, does salt water heal piercing infections?
Using a saline solution or sea salt solution to keep it clean can be one way to keep your piercing site free from infection as it heals.