Are fat injections with PRP the same as a fat transfer with PRP? And how well does the fat take hold around the temples?

Yes, this refers to the same thing and you can have fat transferred to the temples. Fat transfer technique is what 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 then add Sculptra (depending on area) to improve final results. I recommend getting a formal evaluation with an expert.