Is this indentation on my thigh something to worry about?

Hello doctor,

About a week ago, I noticed this indentation on my left thigh. It looks like a long line across it. It is most visible when the leg is placed horizontally and the muscle is relaxed. I cannot see it when I stand up or bend my leg. I think it appeared recently because I would have noticed it before. It is much more pronounced when I pull at the skin and fatty tissue. You can see it in the photos. All the tissues and muscles feel normal and there is no pain, swelling, lumpiness etc. Both the legs are symmetrical and the tissues are mobile and elastic. There is no adherence anywhere that I can tell. What is this? It looks more like it is related to the fatty tissue. But, it did appear or I noticed it immediately after starting to work out. So, could it be related? If there are no other signs, is this something I should worry about, like a cancer sign? Or should I relax about it?