Help! Weight gain...

During pregnancy I did so good not gaining weight, then out of no where I gained like 20 lbs towards the end of my pregnancy within like 2 weeks it felt like. My arms got so huge, and I’m so self conscious of it. Do any of you have tips or what I should do to help lose the arm fat?? I’m already eating healthy. I just don’t know what exercises I should do! Would jump roping help?? I just found mine I used to use.