6 months post-op: pea sized bump on tip of nose after septorhinoplasty

It is difficult to tell from the pictures what exactly could be going on. Some things we think about include residual swelling, scar tissue, displacement of grafts, etc. I strongly recommend that you make a follow-up appointment with your surgeon to discuss and be evaluated in-person. Best of luck!

Thank you for your questions and for sharing your photographs.
Swelling around the tip of the nose is usually the last thing to settle and will take at least 12 months, only then you would be able to see if you require any treatment. I appreciate that it is frustrating, but I am afraid you need to be patient for another 6 months before one can assess any further surgical intervention.
I would advise you that you consult with your surgeon. He/she is in the best position to advise you as only your surgeon knows what were the findings during your surgery and what techniques and suture materials were used during your operation.
Best wishes,