Whitening of foreskin. Any problems.

Hi, last year I noticed that my foreskin's color (a small part of the top) has changed to white. Due to this color change it became difficult to pull the foreskin back as whenever I pull the foreskin back it starts to pain a little. In erect position it becomes almost impossible to pull the foreskin back and the pain also increases because while pulling the foreskin back that white skin contracts inside a little just like what happens when we put a tight rubber band on finger. The intercourses also becomes painful when done with retracted foreskin. And after intercourse that white skin gets bruised. I had it checked up with a Urologist and he said this is nothing to worry about as it's only pigmentation of skin and he didn't bother to listen to my problem in full detail. Please advise on this and also suggest the specialist I should meet i.e. Dermatologist, Urologist, Sexologist etc. FYI - I do not have Phimosis as earlier the foreskin was retracting fully without any problems.