I have acne black scars. using persol ac 5 cream. 4 days afyer usage i got redness n light swelling on affected area. is it notmal. can i use regulr ?

Normal: Benzoyl peroxide often causes dry, irritated skin. When you write "acne black scars" it suggests post-inflammatory pigmentation. A retinoid may be your best bet. Adapalene or tretinoin are available at different strengths and different forms. Expect some irritation and expect to use it for a long time. If you suffer active acne the best therapy is oral spironolactone.