microneedling works by creating tiny controlled punctures in the skin which triggers your body to produce more collagen and elastin as part of the healing response, that new collagen is what gradually fills in those pitted areas over time. as for pain, most providers apply a topical numbing cream beforehand so you mostly feel a vibrating or slight scratching sensation rather than sharp pain, it varies a lot by individual pain tolerance though. for acne scarring specifically you typically need multiple sessions spaced about four to six weeks apart because collagen remodeling is a slow process, most people notice gradual improvement starting around session three but real visible change in texture usually takes somewhere between four and six sessions total