Please help!!

MaKayla • 21• Married to my Middle school Sweetheart! • PCOS • due with #1 on 07/01/2020

Okay so I get this rash on my arm from time to time and its hella itchy!! Ive already asked my dr about it and he said i am fine and that pregnancy brings alot of skin changes .. He said im ok.. I still want to know what this is and what may be some possible options! Ugh . any advice is appreciated thank you . also I'm 17 weeks 1 day for anyone wondering.