irritation around tip of penis

i have recently noticed a skin irritation around the tip of my penis , it is literally where the shafrt and the mushroom tip meet. this skin is red and looks inflamed, i do no masterbate more than maybe once a week so thats not it. for  a whiole now i have had what looked to be dry skin cover alot of this area and it would just come off in the shower and i would put neosporin on it and go. .....now its been a few weeks and there is no dry skin anymore. i just have an irritation that i can not get rid of where my shaft and tip meet. i have had no bleeding, just bad irritation. it doesnt cause itching either. it stings a little while the friction of having sex is going on. my girlfriend of 7 years and i both are clean of any stds as well. ....i have tried everything from what i can think. i dont know what to do. please help me .....this is making sex hurt and i am constantly worrying about what the area is going to look like everytime i pull down my pants.      once again though, its not on my shaft or on the tip. its the crease where the shaft and tip meet. its red and irritated and i cant get rid of it.

[Nate26]

This is the exact problem I have been having for almost 2 full years. It has destroyed me emotionally and I have been tested for std, all were negative, I have been to the doctors 7 times and nothing helps. Did you ever get this problem taken care of? Please let me know so I can try it too. Thank you so much.