What Causes Rashes In Lower Legs?

hello im a 34yr old female,i am sexually active ive noticed a small rash like on my lower legs they look like tiny water bubbles but they wenta wayuwhen I rubbed cream on it the nect two days but it left a dark spot om m ylegg I scratched it now I see more is that a sign of hiv I was alao sitting outside alot getting bit by mosquitoes and I have allergys plz help tthe rash goes away in 2days. what dos hiv rash look like