Bad skin rash in my right butt cheek

Age: 24 (male)
Skin Color: Dark
Country: Sri Lanka

I have these skin diseases in my lower body,

1 - Rashes in my upper groins in both left/right, some times those are gets extremely itchy, and also there's a rash my right waist, which started few years ago as small circle in my left side of the waist, and it was moved slowly to the right side,
Image (my lower body):
http://bit.ly/9T5RSS

2 - And I also have a very bad rash in all over my right butt cheek, which was started few month ago (about 2), and it also gets extremely itchy most of time, (left butt cheek is barely fine)
Images (right butt cheek):
http://bit.ly/a0dI6T
http://bit.ly/cKagIn
http://bit.ly/aYlyrY
http://bit.ly/anhUJA
http://bit.ly/cux014
http://bit.ly/dDnBGY

Image (left butt cheek) :
http://bit.ly/clvUUh

please help!