I had several arm fractures operated on, about a year before I went keto. A couple of the scars became minimally visible right away, even before keto. But one scar in particular is now a lot better. Is that from my keto diet, or simply from the passage of time? I couldn’t say. What I am pretty sure of is that the improvement didn’t result from using Vitamin E or that silicon ointment, both of which I tried, to no effect.
It is possible for autophagy resulting from being in ketosis (and from fasting) to reduce scar tissue, at least somewhat. Whether autophagy could have a noticeable effect on keloids is a question to which I don’t think anyone knows the answer. My guess would be that even with regular scar tissue, the process would take some time, quite a long time with keloids.
ETA: I just remembered that the accident that caused the bone fractures also left me with a very small keloid bump where my left elbow got scraped, and it slowly started to improve, beginning about six months after I started a ketogenic diet. I just realised that it is now completely gone, after three years. So perhaps the improvement in the surgical scar I was so concerned about could also be from eating keto, who knows?