Diagonal Lines after Rhinoplasty
You have what is called an "inverted V deformity" which is secondary to collapsed central portion of your nose. This can be corrected with the placement of cartilage "spreader " grafts. Unfortunately a revision will be necessary.
Diagonal lines after rhinoplasty
In most cases removing the bump on the bridge (or dorsum) of the nose entails reducing the height of the cartilage and bone which create the bump. After the top of the cartilage portion is reduced the cartilage portion may collapse inward. In these cases cartilage grafts can be placed to counteract the tendency of the walls to fall inward. In your case it appears that the cartilage walls have fallen in relative to the upper bony portion of the nose. This results in the shadow "line" which is the area where the cartilage drops in relative to the nasal bone above. There are both surgical and non-surgical options. If the collapse is causing breathing problems secondary to narrowing of the airway then surgery will be needed. Cartilage grafts can be used to reposition the cartilage sidewall of the nose so that it is corrected. If the concern is purely aesthetic then the bridge of the nose can be re-contoured with injectable fillers to camouflage the shadow line.
Diagonal Lines after Rhinoplasty
Thank you for your question and for submitting photos. As a rhinoplasty surgeon I have nothing to add to the comments below especially the detailed answer from Dr. Lentz. If this appearance bothers you it could be corrected with a surgical revision.
I would advise you to speak first to your surgeon. You could then seek a second opinion if you wished. Please make sure that the plastic surgeon is board certified and has an expertise in rhinoplasty.
The inverted V deformity that resulted after your Rhinoplasty is from collapse of the mid vault of your nose
Your nose is a very complex structure. There is the tip which gets it's shape from your lower lateral cartilages. There is the mid vault which is made up of the upper lateral cartilages which attach over the septum which is the cartilage that separates the two sides of the nose. Then there is the boney dorsum. Your hump is made up of the boney dorsum on the top which attaches to the mid vault. Your hump is removed by filing down the boney dorsum and removing some of the upper lateral cartilages and septum. The inverted V deformity comes when after the hump is taken down the upper lateral cartilages are not reattached over the cartilage septum. When this happens the upper lateral cartilages slide down the sides of the septum and thus the inverted V deformity.
Unfortunately the only way to correct this is to re operate on your nose and reattach the upper lateral cartilages over the septum. If you have or had some mid vault collapse you may need to have some spreader grafts. These are cartilage grafts usually taken from the septum (donor site) which are sew on to both sides of the septum and the upper lateral cartilages are then sewed over the septum and spreader grafts.
It is not clear if your boney dorsum is wider than your nasal base. If it is you would be best served by having the dorsal bones of your nose cut to narrow this area also. I would recommend that you seek a second opinion from a Board Certified Plastic Surgeons who does frequent rhinoplasties, consult them, ask to see photos and then make an informed decision.
Inverted V Deformity
As Dr. Fleming pointed out, the deformity in the pictures shown are known as an "inverted V deformity". This is caused by a mechanical disarticulation of the upper lateral cartilages (which shape the middle portion of the dorsum) from the nasal bone. This will not resolve over time and will require a revision Rhinoplasty to correct.