white head blisters

I have this little white blisters underside my penis for about 6 or 7 months, I was scare got tested for HIV,gonorrea , syphylis, Chlamydia, herpes n all came negative, I thought it was the yeast infection so I used a cream for 15days but still there n the doctor said that it doesn't look like genital warts n she thinks its irritation so she told me to leaved for a couple days , but I think I getting a little more so anyone know about a cream or something I can use ? Also when my penis is erect the blisters are 3 times smaller than regular n when I finish there are 2 times bigger so I dont know what is it somebody help!!!!!! Please

[gracefromHHP]

you should see a dermatologist at this point for a more thorough work up.

grace