Hello, Thanks for writing to Health Care magic, I am Dr , Muhammad Ahmad , I have read your question closely, I understand your concern and will be helping you with your health related problem. Unilateral swelling og the leg is usually always pathological you didn t mention pain in the calf so it might not be the more dangerous deep vein thrombosis but it might be some venous issue or a local obstruction to draining system , in any case you better get a checkup , your doctor might want to do some tests for it like doppler studies of vessels an other more advanced tests. There doesn t seem anything to be emergent but still this needs to be checked up by a doctor. I hope this answered your question, If you have more queries I am happy to answer you. Regards. Dr.Muhammad Ahmad