How can I know why I have small scratch on the corona of the glans

Small scratches or abrasions on the corona of the glans can occur due to various reasons, often stemming from minor trauma, friction, or irritation. Considering you noticed this after a shower, it could be due to vigorous scrubbing, drying with a towel too harshly, or using a soap or shampoo that irritated the sensitive skin in that area. If you’ve recently engaged sexually, friction from intercourse or masturbation can also be a factor. Since there’s no pain and just sensitivity, it doesn’t seem severe, but you should continue to monitor it. Make sure to keep the area clean and avoid irritants like harsh soaps or tight clothing that might rub against the affected area. If possible, give the area some time to heal naturally; this typically means a few days without additional irritation. Avoid re-exposing the area to similar situations that could have caused the initial scratch. It’s also wise to refrain from any sexual activity until it heals fully to allow for recovery without extra friction. Apply a mild, non-scented moisturizer or an antibiotic ointment like petroleum jelly or something similar if you notice any signs of dryness or infection developing, but limit application to avoid making it worse. However, if the sensitivity persists beyond a week, the area becomes painful, develops discharge, or if you see signs of infection — like increased redness, swelling, or warmth — you should see a healthcare provider for a proper examination. The doctor may look into other possibilities like dermatitis, balanitis (inflammation of the glans), or infections, which could require more specific treatment.