As you are getting bubbles in the skin and you are having Lymphoedema too,you should go for a Higher antibiotic with action more on Gram positive group of organisms.
As it is not relieved after so many days,it is better to have multiple relaxing incisions
of 1 cm over affected area.In my experience,it gave good and fast results.
Any infection in the leg may lead to cellulitis
,particularly in lymphoedema patients.
So,you should keep your lower limb well covered,not to sustain even minor injury
Wish you speedy recovery.