Sensitive Testicle, Skin Cracking. Treatment?

Okay please help, im 17 years old and ever since about 11 ( well at least thats only when i actully noticed it) my left testicle seems a bit odd. It seems like it almost exploded, or cracked and has always been more sensitive than the other one. Recently it has been worrying me because i dont think its normal. I went into the doctors when i was 14 about how i thought something maybe wrong, he didnt say anything, but i was also very nervous and unclear on what the problem was, and i feel he did a half job because it only took like 2 minutes. Im planing on going again just would want to know if theres anything i should look out for or perhaps any answer at to what it could be. thanks much