I suggest you contact your plastic surgeon to evaluate your arms and determine the cause of your concerns. Seromas are best treated early so they don't keep coming back. Best, Dr. Aldo
Most of the time, a seroma needs to be drained, unless it is very small. This can be done in the office with a needle and a syringe. You need to return to your plastic surgeon for followup and have the seroma drained. Best wishes.