Swelling in a leg muscle with little pain can be due to a muscle strain, minor injury, fluid buildup, or sometimes a circulation issue. You can try rest, keeping the leg elevated, applying ice or a warm compress, and gentle compression with a bandage. However, if the swelling is persistent, see a doctor to rule out conditions like infection or a blood clot.

Long-term use of Lasix can sometimes cause weakness due to fluid or electrolyte imbalance. He should not change or stop the medicine on his own and must consult his doctor, who can check blood tests and decide whether a dose adjustment or alternative treatment is needed.