Hello,
It can be due to contact dermatitis or milia skin. They are white pimples that occur mostly on the upper cheeks, nose and chin. The best way to prevent milia is to avoid treating your skin with excessively harsh chemicals and to limit sun exposure. Also use good quality cosmetics and exfoliate your skin regularly. If still the symptoms persist then chemical peeling or laser removal can be done.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your dermatologist. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
Then you're most likely right. If you were feeling irritation from the salt water these little bumps are probably the result.