Will 150cc of fat give me an acceptable BBL result? What does the hardening mean on injection site?

Unless you are very petite, 150 cc of grafted fat is not a lot. Without photos it is very difficult to evaluate the potential impact of such transfer on your appearance. You should keep in mind that not all grafted fat cells will survive. Hardness at the injection site can mean a lot was injected, or it can mean other things. You should follow up with your plastic surgeon. Good luck!

In general, I have not found that 150 cc's will do much for most patients. That might be good for a touch-up for some.

Even if you are very petite 150cc is not enough to make a noticeable difference over the long term. 150cc into each hip can be enough to make a nice result there, but not the buttocks. You lose 30-50% of the fat volume over the first 3-6 months, so 150cc spread over your buttocks isn't enough once the volume goes away. Unless you are incredibly skinny, your plastic surgeon should be able to get more than 150cc of fat when liposuctionting multiple areas of your body. Hard areas at the injection site can be swelling, bruising, hematoma, fat necrosis, etc. It is best to ask your PS to look at these areas to make sure everything is ok.