There's this nasty looking rashes on my body that has refused to go. I've done many tests including HIV, all came out negative. No medications seem to work either. Any useful advices would be appreciated. Thanks a lot.

An infection for sure but I think you need to add more info.. Like when did you notice this, how long has this been, does it itch, what did the medical personnel say when you met him/her(if you did), etc.. That will help people understand your condition, how it came about and maybe there will be more inputs than views, just saying though.