It may be the needle moved & tissued that is some of the fluid went into your arm rather than the vein. Mine did for a long time & I was in a lot of discomfort from the area. My skin was tight, hot & uncomfortable.
A friend advised compression, elevation & massage. The massage is painful, but if kept up on a regular basis breaks down the inflamed area. You can feel the lumps of fluid under your skin & them almost popping as they are released. It took several days but worked eventually but as I say mine was several hours worth of tissuing & stretched from wrist to almost elbow. Hopefully yours is only a small area & easily eased.
Of course I may be wrong but may be worth a try.