Thank you for your question and photo. Yes it is too late now. Although back boards or foams do not create the dent you are looking for, I use double foam pads I customize for the patient right after surgery. It is important to adequately sculpt the lower back, by removing the lower back fat pad. The space created between the skin and the backbone and paraspinous muscles if not compressed to "stick" and heal together, will accumulate fluid, more scarring and poor shape. You are too late to recreate this dent at this stage of the healing. It is also possible that your surgeon did not remove all the fat in this area. Wait until you are healed and be reevaluated. Good luck with healing.