Looking at the swelling its very unlikely that this developed in just one or two days as told in the history.
Secondly Is it present on both the legs or just on left legs as shown in photo
If its acute in onset is your mom running fever.
Has she
diabetes / Hypertension / any heart related issue in the past
Next Steps
Urgent CBC, KFT, urine routine, BLOOD
sugar
ECG
Health Tips
Dont waste time for online views urgently rush her to a doctor for investigations and clinical assessment
MAY GOD KEEP HER SAFE AND HEALTHY