Wiser medico type folks there .This place is deep with knowledgable people.

Not to alarm you Laura...the situation you're in could be a possible blood clot.

Warning Signs and Symptoms of Blood Clots
Swelling in the leg or arm.
Tenderness or cramps in the leg.
Out of breath, or shortness of breath.
Passing out or feeling lightheaded.
Chest pain or back pain when breathing.
Leg discoloration, either a red or blue hue.
Overdrive, when your heart is racing.
Time to call 911.

Although, an ice bath (for the arm)in epsom salts have been known to lower pain and swelling

That sounds awful.I am sorry you have to deal with that garbage,I am out of my depth to help with this Have an amusing ditty in lieu of other things .......... one https://youtu.be/BiPoA-bEjQo

Massage and "milking" it towards the lymphatic system. My mother has swelling of her arms due to Lymphadema in her arms so we do gentle massage to stimulate her lymphatic system and gently milk her arms towards her arm pits. It helps the swelling go down. The compression sleeves. I also use compression sleeves to keep my arms from swelling and we do the same thing on me when my arms are feeling tight.