Reasons for swollen lips :-

Crohn's disease may lead to lip swelling.

Chromosome 7p duplication syndrome

dysplasia ectodermal, hypohidrotic, autosomal recessive

 Lip inflammation in eczema and psoriasis

 Lip swelling as in glucagonoma 

Hereditary angioedema-

Stomatitis in herpes

Hives - lip swelling

Melkersson-Rosenthal syndrome - lip swelling

Mucopolysaccharidosis II enlarged lips

Myxedema - swollen lips

 trauma heat and cold effects .

Trauma