Red Rash on my ?

Hi im 15 and nearly 16 and I have had a red rash on my which has now been there for about 1 month. This red rash is kind of streaky which looks like red lines on my . These rashes are not itchy, they are not soar and they dont release any fluids. I have researched into this and cannot find anything which describes the same symptoms as what i have. However the closest thing i have seen is psoriasis. I do not want to tell my parents yet until i have abit more confidence to as what it is i have wrong with me. I've had , but used protection so i am certain it is not an STD. I have tried having baths to try and improve the condition however, it hasnt made things better. I am scared that it may get worse and is uncurable. Has any body got any idea to as what this rash may be and has anybody got any advice which i could follow? Thanks.