What is Omnibiocide used for? What is its effectiveness against lichen planus?
Omnibiocide is an over the counter product reported to contain Benzalkonium Chloride (NDC 70414-101), which appears to be used as a disinfecting agent. According to wikipedia, Lichen planus is an inflammatory condition. You may wish to ask your doctor or a pharmacist whether an antihistamine, topical steroid, or other kind of medication would be appropriate.
"The mainstay of localized skin lesions is topical steroids. Additional treatments include retinoids, such as acitretin, or sulfasalazine. Narrow band UVB phototherapy or systemic PUVA therapy are known treatment modalities for generalized disease."