According to The Mayo Clinic, acne treatments that contain a few key chemicals are the most effective choices to eliminate pimples. Benzoyl peroxide, which The Mayo Clinic notes is the most effective, kills the bacteria that causes acne and cleans clogged pores. Salicylic acid promotes the shedding of skin cells that can clog pores and cause acne. Both of these chemicals can cause mild side effects.

Excessive Dryness

Drugs.com warns that patients using formulas with benzoyl peroxide may experience excessive skin dryness, which can lead to red patches or even peeling skin. If this occurs, the concentration of the active ingredient may be too high in the solution you've been prescribed. Talk to your dermatologist about trying a different mixture.

Stinging and Redness

The Mayo Clinic warns that stinging and skin redness are side effects of both benzoyl peroxide and salicylic acid solutions. These side effects should be mild and should fade with time. If you experience excessively painful stinging or prolonged redness, be sure to talk to a dermatologist.

Hair Color Change

When you apply products containing benzoyl peroxide, be careful not to rub any into your hair or eyebrows. The product can bleach and discolor your hair. It can have the same effects on your clothes, so be careful not to get it on your sleeves or other articles of clothing.

Allergic Reaction

Drugs.com notes that the products can also cause a mild reaction if you have allergies to the active ingredients. The allergic action may include itching and swelling in the affected area. Be sure to talk to your doctor if you suspect you are allergic to the active ingredient in your acne medication.