Contact Dermatitis: This is the most likely diagnosis due to the common occurrence of allergic reactions to substances like cosmetics, soaps, or metals (e.g., nickel) that come into contact with the facial skin. The reaction typically presents with redness, itching, and small blisters.

Atopic Dermatitis (Eczema): A chronic condition characterized by itchy, inflamed skin. It can be exacerbated by allergens and is common on the face, especially in children but also in adults.
Urticaria (Hives): An allergic reaction that can cause raised, itchy welts on the skin, including the face. It can be triggered by various allergens, including foods, medications, or insect bites.
Angioedema: Similar to urticaria but involves deeper layers of the skin, leading to swelling, often around the eyes, lips, or tongue. It can be a part of an allergic reaction.

Anaphylaxis: A severe, life-threatening allergic reaction that requires immediate medical attention. Symptoms can include swelling of the face, lips, tongue, or throat, which can lead to airway obstruction, along with other systemic symptoms like hypotension and tachycardia.
Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN): Rare but serious disorders usually caused by medications. They can start with facial swelling and skin lesions that can progress to widespread skin necrosis and detachment, involving mucous membranes as well.

Erythema Multiforme: An immune-mediated disorder that can be triggered by infections or medications, characterized by target-like lesions on the skin, including the face. It can also involve mucous membranes.
Fixed Drug Eruption: A type of drug reaction that causes skin lesions in the same area each time the particular drug is taken. While not exclusive to the face, it can occur there and is important to consider in patients on long-term medication.