Thanks for your query.Based on the facts that you have posted it appears that you have accumulation of a smegma
over coronal sulcus(Groove) of the glans penis
This is a natural secretion of glands situated in penis which acts as lubricant and protects the glans from exposure to external atmosphere and to keep it moist.
When ever this secretion is xcess this gets precipitated what is called as Smegma.
Please observe good personal hygiene and clean the area with warm water while taking bath.Do not worry at all .You do not need to take any medication for this.