Answers: Hello, I am assuming that you are speaking of an uncircumsized penis. Here is an answer from a doc.
http://en.allexperts.com/q/Urology-Male-...
Best Wishes!
Dry sex can cause this. The solution is to product sure their is always plenty of lubrication. Additionally, verbs and moisturize the foreskin after sex for a while to prevent it from being a problem. As for treatment after tear, a petroleum jelly ointment (like Neosporin or Lip Balm) will cut health-giving time drastically.