Hello 
Thank you for trusting HCM 
Usually, there will be a white creamy layer on 
glans penis (rounded head of the penis), is called 
smegma formed by a combination of shed 
epithelial cells, oily secretion from glans penis and moisture. 
Formation of smegma is normal phenomenon. But it is associated with rash, itching foul smel then there is a possibility of infection. 
Are you diabetic??? Since how many days your suffering?? Have you using any drugs? Are you married??? 
Common possibility according to your history is your suffering from 
balanitis due to yeast infection but as such you told Al tests are negative. 
What about culture of creamy layer, wet mount. 
Treatment :
1.Till that time take Candid b gel for local application. 
2.maitain good personal  hygiene. 
3.avoid new cosmetics may cause 
allergy. 
Consult your doctor if symptoms not improved.