What is the cause behind my weird V shaped columella/tip? (photo)

To have a complete evaluation of your case, it is important to see photos of your profiles, and that will add more information to see what can be done to decrease the V shape. This can be from alar retraction, supratip fullness, or hanging columella. All these could be present at your case and different surgical techniques can be use to correct it. Please check with a Board Certified Facial or Plastic Surgeon for a complete evaluation of your case.

The shape reflects the anatomy of your lower lateral cartilages. They can be modified with surgery. Chin implant surgery has long been touted as a simple operation that reliably gives good results.

The nose is a three-dimensional structure, so A full set of photographs are required to make any determination about surgical alterations to it. The columella is best  seen by a side view, not a frontal view. The bulbous tip can be reduced, the hanging columella can also be reduced and the dorsal hump can be shaved down along with refinement of the tip and the bridge line. Digital computer imaging would be helpful at the time of the consultation to give the patient an idea of what can be accomplished with your nose on your facial features. For more information  and many examples, please see the link and the video below

Hard to give an opinion with a single photo. It appears that you have a fair amount of swelling, which indicates that your rhinoplasty was recent-within the last 3 months?Lateral and base views would be helpful to form an opinion.

This one picture suggests that you have a hanging columella which can be lifted very easily with a small procedure under local anesthesia. A profile view would be helpful.