i think i remember reading that it can effect both the upper and lower lips, but it is rare.
also fyi i was reading an article focused on cheilitis glandularis and there was some interesting information which applies to any vermillion disorders:
"If predisposing factors cannot be identified or eliminated, conservative treatment should ensue, including the use of topical steroids, intralesional steroids, systemic anticholinergics, systemic antihistamines, and/or Antibiotics . If conservative therapy fails, as in our clinical cases, surgical intervention is often required to reverse lip eversion and remove the sources of inflammation of the minor salivary glands [9, 12]. Surgical options include cryosurgery, vermillionectomy, and/or labial mucosal stripping, as advocated by Stoopler et al.  We therefore also agree with Nico et al.  that in cases of lip diseases, a single punch biopsy may not be a suitable method for accurately diagnosing this subset of patients and that, if vermilionectomy is performed, careful histological examination of the entire excised specimen (serial sections) is mandatory."
very interesting. i've always thought that the single punch biopsies werent enough.