Proactiv is an over-the-counter topical acne treatment that contains the active ingredient benzoyl peroxide. The three-step Proactiv system includes facial cleanser, toner and lotion, and is indicated for daily use. Though improved skin clarity can begin within three weeks of treatment onset, it can take up to 12 weeks for certain people to notice an improvement in their skin, explains PDRHealth. People who have questions or concerns regarding the potential side effects of Proactiv should consult a doctor for further information.

Rash

People can develop a mild, red skin rash at the site of treatment, warns Drugs.com. The rash can appear immediately after applying Proactiv cleanser, toner or lotion and may persist for a few minutes or hours following treatment. People who develop a persistent or severe red rash that is tender to the touch should contact a doctor.

Dryness, Itching or Peeling

The skin at the site of Proactiv treatment may appear unusually dry as a side effect of this topical medication, reports MayoClinic.com. The affected skin can begin to flake or peel and can become itchy. These side effects of Proactiv may be most apparent to people who have used this topical treatment for several days.

Stinging or Warm Sensation

During and immediately following Proactiv skin application, people can experience an unusual stinging sensation at the site of treatment, according to Drugs.com. Additionally, certain people can develop a feeling of warmth across treated skin regions. These side effects of Proactiv typically resolve shortly after application, but can be accompanied by skin redness.

Allergic Reaction

Certain people can experience a severe allergic reaction to Proactiv during initial use of this topical acne treatment. An allergic reaction to Proactiv can cause small, red bumps to appear across treated skin. The treated skin may itch intensely and can appear swollen, scaly or blistered. People who develop allergic reaction side effects following Proactiv use should stop using Proactiv and contact a medical professional. To avoid severe skin reactions, Proactiv health professionals advise that people first apply this medication to a small area of skin for several days and monitor how the skin responds. People who experience a severe skin reaction at the skin test site should not use Proactiv.