What Causes Small White Spots In The Head Of Penis?

hello doctor i m 21 years old. i had unprotected sex with a prostitute 3 years ago.i tested HIV 2 times and result are negative 6 months ago.but i m so confused because 3 months ago there are some very small white spots in the head of my penis and around and sometimes its itching.i m so scared.what should i do now.Are there anyway to getting HIV? and after having that spots i m so scared to test HIV again.and everyday i m thinking about this and its so hard to live now.and these thing are so bothering to my studies.please help me?