Thanks for coming to HCM
I think you must have told the site of lesion i.e at the angle of the mouth or towards left or right side repeatedly.
Allergic reactions may be a cause for lips swellings,but usually is associated with swellings at other sites, itching, rashes and is particular to some allergens like food stuffs.
Repeated swelling in a particular side right or left which may end with pustules may be due to herpes
infection often called Herpes labialis
if it involves angle of mouth then may be due to vit. c cheilosis...
so the treatment depends upon the cause...
if allergic then immunotherapy
, antihistaminics and in certain cases antihistaminics...
if cheilosis then tab vit.c 500mg twice a day
if herpes labialis then tab aciclovir
so meet your doctor