Blood clots. Often, veins deep inside the legs get larger. They may induce leg ache and swelling. Search for medical enable for ongoing leg discomfort or swelling. This tends to mean a blood clot. If you worry about how your veins appear and feel and self-care actions haven't served, see https://www.sgvascularctr.com/what-surgery-is-available-for-varicose-veins/