Hi, PRP is made by concentrating your own blood and is great for under the eyes precisely because it does not carry the risk of foreign body reaction such as nodules. It is almost impossible for PRP itself to have caused this unless there was something else added to the PRP or if it was contaminated. I would recommend that you contact the practice where you had the procedure done to find out if they combined the PRP with any filler. This is a common practice to help the PRP effects last longer, but the filler can settle just above the ligament in that underlie compartment. If it was a hyaluronic acid filler, it can be dissolved with hyaluronidase.