Are these bumps scar tissue, or was my nose over-corrected and scooped out too much? Will I need a revision rhinoplasty? (Photo)

There is likely residual cartilage (lower bump) and bone (higher bump) remaining after the original surgery.  I would recommend a revision wherein the excess cartilage is excised directly and the bone rasped down.  A needle will likely not accomplish this.  

Thank you for your question and the photos. Without examining you in person and palpating the nose, it is essentially impossible to determine what the nature of the irregularities are. However, it is likely that the "bumps" are not related to scar tissue only but rather to irregularities of the underlying cartilage, which were likely present from the get-go and camouflaged by the post-operative swelling. Now that the swelling subsided, they became more visible. However, only your surgeon knows what exactly he did and what the likely cause is. I recommend that you follow-up with your surgeon and adhere to his recommendations. "Needle shaves" are sometimes done to smoothen areas of excess cartilage, typically when a cartilage graft was placed. Best wishes!

Your surgeon is on the right track. And if there is scar tissue, steroid will help but give it at least 2-6 weeks. The needle technique saves you further surgery or incisions by gently shaving the bone a bit. Numbing solution is used first so it wont be painful. Not to worry, its very minor compared to what you've been through already :)