I have a bump and line in the middle of my nose after rhinoplasty. How did this happen and can it be fixed? (Photo)

Although it's difficult to provide a definitive answer based on photos alone, it does appear that there is an irregularity in the bone and cartilage of your dorsum.  At 4 months you are still fairly early in your recovery so your nose will change in appearance, so your bridge may or may not improve.  Revision rhinoplasty may be necessary to smooth the contour, but shouldn't be considered until the nose is fully healed.  

Hello,Thank you for your question, and included images.It appears that the transition between the upper lateral cartilages, and the lower lateral cartilages is more pronounced than I would like to see.  This is a particularly complex area, and the best measure of how significant this will be, is best determined after you fully heal.  This may take several more months. I agree with your surgeon's advice to massage and remain patient.Thank you,S.P. Maggi, MD, FACSAustin Plastic Surgery Center 

   It is always difficult to speculate on something of this nature.  There does appear to be swelling, which will mask the nature of what may develop.Kenneth Hughes, MDLos Angeles, CA

Without actually seeing the internal anatomy of the nose at this time- it is limited to determine an explanation. The nose is comprised of -- skin, bone and cartilage. The surgeon has control over the cartilage and bone under the skin. Therefore, it is imperative that the surgeon skillfully sculpt the bone and cartilage under the skin so that the skin can reflect this internal sculpting. Healing occurs at differing rates-- what you see could be just swelling. Time and massage will tell. If after a reasonable amount of time--- you are still concerned-- time to possibly have a revision.

There seems to be some asymmetry of the height of the cartilaginous dorsum versus the bony dorsum. There's also obvious swelling. This should be allowed to resolve before a revision but I do think a revision will be necessary.