Fat loss on forehead and temple - I don't want filler in the high risk area. What else could work? (photos)

I have had some fat loss in the last couple of years du to aging but also due to hifu treatment. I have visible line on my forehead where I don't have any left and my forehead therefore looks bumpy. Tried to have it filled with filler a while go but the result was super bumpy. A few weeks ago I had some Pdo threads to stretch the skin so the fat loss is less visible. However i am wondering what other treatments there? Does a r injection carry the same risk than a dermal filler?