What white pill says icn n22?

The white pill imprinted with "ICN N22" is identified as Diphenhydramine Hydrochloride 25 mg, which is an over-the-counter antihistamine commonly used to relieve symptoms of allergy, hay fever, and the common cold. It can also be used as a nighttime sleep aid due to its sedative properties. Always follow dosing instructions and consult a healthcare professional if you have any concerns.