dry cracking skin, on penis

[whatswrong804]

I am 19, and un sure about what this is. I have had this problem a few times before, but took nothing from it.. but it is serious. the skin is very dry around the foreskin area i think its called right underneath the head of the penis. and only that area is itchy and dry. no where else on the penis. everytime i get an erection, the skin begins to crack, and looks like stretch mark, but my penis has not gotten bigger it had seem to have gotten even smaller. just having the thought behind my mind that it hurts like hell prevents me from having sex.. it is a serious problem.. i cant have sex with my girlfriend, the urge of masterbating (masturbating) was lost, and it still is very very very very itchy... and dry.. im not sure what this is. at first glanse i looked into this and i thought it was an Yeast Infection, and told i should use conestan, and other ointments. i have not used it because others are unsure of what to make of this. so doctor what do you think?
I want to beabled to have sex again. i am very young..

-thanks