What Causes Burning Sensation And Itching In The Vagina With A Welt?

Hi docs my name is Monica and I will get a burning sensation and then an itch followed by a giant welp.then they spread been to er and all I get is an allergic reaction to something.but I have female problems which causes me to bleed 3weeks out of four.could all my bleeding be causing this.it comes and go and seems too be present when I bleed excessively? Please help desperate ....thanks Monica