Thanks for writing to us.
The swelling and redness could either be due to angioedema
or cheilitis( causes could be many like irritant or allergic reaction
, sun exposure, cheilitis granulomatosus etc). To treat the condition it is imperative to delineate the underlying cause first.
However in general, use a sunscreen containing lip balm. Take tablet cetirizine
for few days and apply a mild steroid
cream over the lips.
Hope that helps. Take care