Why Fat Transfer Isn't Good for the Temple and Above the Brows Augmentation?

Hello dear doctors, I have depressions on the temples and above the brows. I already had fillers who did wonders but it's way too expensive because i need a lot of volume. I went to see 2 doctors and they disagreed to do fat transfert on these areas as it seems that the skin is too thin and i'd probably have some bumps and lumps. i've red some differents patients testimonies and they were overall happy. is there any technical skills to avoid bumps in these areas? thanks a lot for you help