I hit the tip of my nose 6 months post rhinoplasty could I have caused any harm to my results?

You are still healing after your rhinoplasty and so yes, your nose may be a little more susceptible to damage than usual.  However, the cartilage in the nose is resilient. Its shape doesn’t change easily; that’s why surgeons must break the bone and cartilage to reshape it, rather than just “pressing” it into a new shape.
Keep an eye on your nose tip: If it seems to be swollen or misshapen, then please consult with the facial plastic surgeon who performed your rhinoplasty. Otherwise, you should be fine. I hope this helps.

Dear riionjal,it is impossible to tell without an examination. In case you are concerned, I would suggest you to consult a board-certified plastic surgeon. Daniel Barrett, MD, MHA, MS 
Certified, American Board of Plastic Surgery  
Member, Am. Society of Plastic Surgery

Best to check with your surgeon, as it is possible for things to shift if the hit was severe enough.