Microdermabrasion is a mechanical form of exfoliating the skin. Once you have had a microdermabrasion treatment, the delivery of any topical skincare product will absorb more effectively. The wait time between microdermabrasion and microneedling treatment should be approximately a month. However, if you have had a HydraFacial, then my recommendation would be 2-4 weeks. A series of treatments would be recommended to assist with improvement of your acne scars. I would recommend a consultation to discuss the treatment guidelines, including a customized plan to achieve your desired results. If the scars are very deep, then likely a deep, surgical laser would be recommended, followed by (after healing) a specific program of skin care that can be provided by an aesthetician. --MaryAnna, BeautyWorksNYC