After standing for too long, her hemorrhoid became thrombosed and very uncomfortable.

thrombosed 是动词 thrombose 的过去分词形式，thrombose 由名词 thrombus（血栓）加上动词后缀 -ose 构成，意思是"形成血栓"。 thrombosed 在这里描述痔疮因血液凝固而形成血栓的状态，表示"血栓形成的"。