What Causes Itchy Red Rashes Around Thigh And Buttock?

I am 16 years old male. I masturbate daily but am not too hygenic. I have two problems. First, i have developed itchy red rashes round my upper thighs and buttocks. It spreads and later became dark (black). Tell me remedy. And second, my semen just drips when it leaves my penis but do not shot out. Can it be due to low sperm count? And also my hair is whitening and falling. What can i do to stop hair fall and grayening? Is it related to masturbation? Thanks a lot if you answer