Efficacy and Safety of Combined Nanofat Injection With Either Platelet Rich Fibrin or Microneedling Versus Nanofat Injection Alone in the Treatment of Facial Atrophic Post Acne Scars

Inclusion Criteria: * Patients older than 18 years of both sexes with moderate to severe atrophic facial acne scars on both cheeks Exclusion Criteria: * 1\. Patients' age \<18 or \>45 years 2. Pregnant and lactating women 3. active inflammatory acne or active infection in the treatment area. 4. treatment of the targeted study sites within 2 months 5. history of chronic diseases (autoimmune diseases, bleeding disorders, taking anticoagulant therapy or aspirin) 6. history of hypertrophic scars or keloid formation tendency. 7. patients with unrealistic expectations.