PRP and stem cells are injected by multiple tiny punctures under the dermis, with or without topical local anesthesia. The process is painless if sufficient topical anesthesia is applied. When injected into the damaged area, it stimulates the tissue, causing mild inflammation that triggers the healing cascade. Thus, new collagen begins to develop. As this collagen matures, it begins to shrink and tightens and strengthens the skin, as well as the tendons and ligaments of the damaged area when it is injected at that level.