It is not too late. Breast lift scars continue to remodel for 12 to 18 months, sometimes longer, so starting silicone tape or silicone gel at 5 months can still help an immature scar become flatter, softer, less red, and less itchy. Use it only on completely closed skin, keep the area clean and dry, and stop if you develop irritation or a rash. Consistency matters more than the exact brand; many patients use silicone 12 to 24 hours per day for several months if their surgeon agrees. The expected improvement depends on what you mean by hypotrophic scars. If the scars are actually hypertrophic, meaning raised or thick, silicone can be useful and your surgeon may also discuss steroid injections, laser, microneedling, or other treatments. If the scars are depressed, stretched, pale, or widened, silicone may have more limited benefit and scar revision is usually considered only after the scar has matured. I would show your surgeon the scars in person so they can confirm the scar type and choose the best treatment plan.