Not seeing any pictures it's hard to make judgement calls but one way would be to do some gentle liposuction to these areas or if it is a small mass then perhaps a small nick in the skin and then extraction.
Fat grafting can be done in individual areas to get more improvement and yes if one hip is larger than the other fat can be grafted to give improvement. I suggest seeing an expert. Best, Dr. Emer.
Keep in mind, fat transfer technique is important for successful fat transfer. I recommend water-assisted fat harvesting which gives pure fat to transfer and combine with platelet rich plasma (PRP) to get the most viable and sustainable fat cells. I combine with Sculptra, depending on area, ...
