Benzoyl peroxide is the main over-the-counter treatment for acne, according to the American Academy of Dermatology. It reduces levels of the bacteria that live on the skin that plays a role in acne formation and sloughs away dead skin cells to prevent breakouts. While it can provide much needed relief if you have acne, it can also cause side effects such as dryness, itching and swelling. If you experience swelling, contact your doctor for further advice.
Some people can suffer an allergic reaction to benzoyl peroxide and may experience swelling as one of the side effects. Other allergic symptoms that may accompany the swelling include hives, itching, rash or shortness of breath, according to KidsHealth.org. Antihistamines provide quick relief for allergic reactions, including angioedema, which is swelling of the dermis of the skin, notes the Merck Manuals Online Medical Library. Antihistamines can be taken by mouth in capsule, tablet or liquid form. Antihistamines can cause side effects such as drowsiness and blurred vision and should not be taken if you're driving or operating heavy machinery.
Applying an ice pack or cold compress to the swollen area has several benefits. It helps to restrict blood flow to the area, which reduces swelling of the tissues, as explained in "Lippincott's Textbook for Nursing Assistants." It also helps to numb pain or itching you may also experience in response to the benzoyl peroxide treatment. Cold therapy can be dry or moist, but the latter penetrates more deeply to control swelling and pain more quickly. If you use an ice pack, place a piece of cloth between it and your skin to prevent skin damage. Do not apply any cold treatment for longer than 20 minutes at a time.
Non-steroidal anti-inflammatory drugs are commonly used to reduce swelling, inflammation and pain. Three of them are sold over the counter --- aspirin, ibuprofen and naproxen. However, if you are allergic to these medications they, too, can cause facial swelling. Do not take them if you've ever had an allergic reaction to them before. Also, consult your doctor before taking NSAIDs if you're on other OTC or prescription medications or are taking supplements.